# Is 11.8V on 12V rail safe?



## quicky008 (Dec 10, 2017)

I am currently using a corsair Vs450 psu on a build with the following specs:

Core i5,gigabyte B75 mobo,4+4=8 gb ram,3 HDDs,750ti gpu.

Usually the voltage on the 12V rail of this psu stays at around 12.1 V under normal circumstances,however I have observed that whenever i start some cpu-intensive application such as a game,it drops to around 11.8V and hovers around that level for as long as the application is running.However as soon as the application is stopped it goes back up to ~12V.The voltage readings were taken using HWinfo64 and hwmonitor(please check the attached screenshot).

Is it safe to continue using this psu in this situation?Can running a system at 11.8v cause any kind of damage to it in the long run?I know that the readings provided by monitoring apps may not be 100% accurate,but i can't help but feel concerned about this as the voltages provided by the 12V rail often have a direct impact on a system's stability.

I am aware that Corsair's vs series psus are generally regarded as unreliable,and so i intend to change it in the foreseeable future.But as of now due to financial constraints,i may have to continue using it for a couple of months longer.Therefore i'd really appreciate if someone could shed some light on this matter.


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## chimera201 (Dec 10, 2017)

The tolerance is +-5% for 12V rail. So 11.4V to 12.6V is the ATX spec. Nothing to worry there.


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## quicky008 (Dec 10, 2017)

^thanks for your inputs,so i should only be concerned if it drops to 11.4V or less,right?I remember reading somewhere else that if the voltage on 12v rail drops below 11.8v then it should be regarded as a warning sign that something could possibly be amiss-do you think this might be true?


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## chimera201 (Dec 10, 2017)

As long as it's between +-5% it won't damage your other components that's receiving power. But yes the higher deviation would indicate that the PSU has poor voltage regulation. But 11.8V isn't really that bad.
You can see some voltage regulation comparison here for some budget PSUs:
600 Watt budget PSUs Battle - PC TeK REVIEWS


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## quicky008 (Dec 10, 2017)

this is quite an interesting set of results-it seems under load the voltage on the 12v rail dropped to as low as 11.5V for the corsair vs 650 psu,whereas for the other 2 psus they stayed at around 11.8V or more.It seems the 12V rail is rather weak for corsair's VS line of psus.

Btw what exactly is drift in voltage?Is it the difference between the minimum and peak voltage readings for a particular rail?


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## chimera201 (Dec 10, 2017)

quicky008 said:


> Btw what exactly is drift in voltage?Is it the difference between the minimum and peak voltage readings for a particular rail?



yes


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## quicky008 (Dec 11, 2017)

earlier tonight while gaming i noticed that the voltage dropped even further to 11.7V for a few seconds.

I dont like the idea of continuing to use this psu,even though getting a new one right now is rather difficult for me.

If i had to buy a new one and had a budget of around 4000,which psu would you recommend?Corsair's Cx 550 is available for around 4.4k and so is Antec's vp 650p-which of these two would be a better choice in terms of reliability and proper voltage regulation?

And how about cooler master's master watt psus-are they any good?


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## chimera201 (Dec 11, 2017)

Corsair CX550 (CP-9020121)


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## gta5 (Dec 11, 2017)

/like chimera said , it is fine .. group regulated units generally are very poor with Crossload performance ( too much load on 12v and very less on minor rails like most modern system)

 but yes CWT made older VS series is much worse in crossload performance /voltage regulation above 220- 250 watts ..

11.7-11.8v is  common with these older group regulated design units under crossload

your system should consume about 230-250 watts max only during gaming and it is fine for that use case.. if it was  330-350 watts + then it would have been a worrying part..

here is a review of your model no - CP-9020096

Sprawność, Test zasilacza Corsair VS450 - jednostka (prawie) dobra | ITHardware

at your system load , the bigger issue with corsair VS is capacitors quality.. so you never know when caps are going to fail.. though they generally hold up good for 1.5- 2 years of use

i would say use it for a month or so , increase your budget and buy Corsair TX 550M instead.. it is superior to both of the above mentioned options and has a long warranty of 7 years for Rs 5700 or get CX 450 and save Rs 800-900 .. if you are lucky you may  get the better model of CX made by CWT  ( from the early available info ) ( there are 2 variants of new CX )  only 1 has been tested till now afaik ..


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## quicky008 (Dec 11, 2017)

Thanks for posting the link to the detailed review of vs450-it seems this psu's 12v rail can drop to as low as 11.6v under 100% load,which doesn't exactly inspire much confidence.My vs450 psu is already well over a year old-so what do you think are the odds that its capacitors might fail anytime soon?

Unfortunately,Corsair's TX550M is priced at around 6000,which is significantly above my budget.Will the Cx450 suffice for my needs?Its available at mdcomputers for only Rs 3400.What kind of capacitors does it have?Can it be expected to last for atleast 4-5 years without any issues?And is its voltage regulation significantly better than the VS series units?


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## gta5 (Dec 11, 2017)

quicky008 said:


> Thanks for posting the link to the detailed review of vs450-it seems this psu's 12v rail can drop to as low as 11.6v under 100% load,which doesn't exactly inspire much confidence.My vs450 psu is already well over a year old-so what do you think are the odds that its capacitors might fail anytime soon?



at 100 % most cheap PSU's behave badly .. some with voltage regulation , some with  high ripple.. your system is going to run at max 40-50 %  capacity of your PSU so look at those values , not 100 % which you aren't going to use ever and they are designed keeping this in mind

i think  it is still good for another 6 months , but ofcourse these are Chinese  stuff so they vary a lot in quality from batch to batch as they have poor quality control .. there have been many members here who have run similar power configuration as yours on VP450P and VS 450 for more than 2 years
(VP450P uses similar caps ).. but all i can say is it depends upon your luck..



> Unfortunately,Corsair's TX550M is priced at around 6000,which is significantly above my budget.Will the Cx450 suffice for my needs?Its available at mdcomputers for only Rs 3400.What kind of capacitors does it have?Can it be expected to last for atleast 4-5 years without any issues?And is its voltage regulation significantly better than the VS series units?



yes , CX uses the new Modern DC-DC design that used to come only in mid-high end power supplies till recently .. so unless something is seriously very wrong , Voltage regulation during crossload should  be excellent as is the cases with most DC-DC units

you can refer this Corsair CXM and check crossload voltage regulation results (CL2)  as a rough reference

Corsair CX650M PSU Load Testing

New "CX" series is slightly better than "CXM" series

There are 2 version of CX series and which 1 will you get is again a game of luck..

if you are not going to add a more than 120 watt TDP GPU to this build in future i think it will last , if you get the CWT's version i think it may last you  6 years ( judging from early limited info/pics ) - no proper reviews yet of CX...


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## quicky008 (Dec 11, 2017)

Thanks for the info.Although i am using a 750ti in this pc for now,i may upgrade to a better one in future such as a gtx 970(provided of course i can find one used at a reasonable price).Will the 450W CX psu be able to handle a gpu like the GTX 970?Can the increased load that will be exerted by a more power hungry gpu cause it to fail prematurely?

Is there any way to check which version of the CX psu i am gonna get before purchase(such as via some kind of serial/batch no etc)?I am thinking of swapping out my vs 450 with a newer one this week as i don't want to continue using it much longer.

Also how reliable are antec's VP 550V2 and VP650V2 psus?Antec claims that they have used "heavy duty" caps in these psus to improve their performance and reliability-are they similar to the CX series psus or even better than them?


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## chimera201 (Dec 11, 2017)

quicky008 said:


> Thanks for the info.Although i am using a 750ti in this pc for now,i may upgrade to a better one in future such as a gtx 970(provided of course i can find one used at a reasonable price).Will the 450W CX psu be able to handle a gpu like the GTX 970?Can the increased load that will be exerted by a more power hungry gpu cause it to fail prematurely?
> 
> Is there any way to check which version of the CX psu i am gonna get before purchase(such as via some kind of serial/batch no etc)?I am thinking of swapping out my vs 450 with a newer one this week as i don't want to continue using it much longer.
> 
> Also how reliable are antec's VP 550V2 and VP650V2 psus?Antec claims that they have used "heavy duty" caps in these psus to improve their performance and reliability-are they similar to the CX series psus or even better than them?



There's the part number I listed before.

CX > Antec VP

Also going from VS to CX isn't much of an upgrade. TXM is a better choice for something like the GTX 970. For PSUs the rule is simple - you get what you pay for. Just remember that  much more expensive PSUs exist than what we suggest.


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## quicky008 (Dec 11, 2017)

Thanks for pointing it out,chimera-i seem to have overlooked  your earlier post.Ideally i would have bought a s12ii unit from seasonic as i have used the 620W variant of this psu already and found it to be very reliable.However i am on a shoestring budget at the moment and therefore i have no choice but to look at cheaper options.

S12II 430 from seasonic is quite cheap and has all jap caps,however this seems to unavailable at wherever i look.Hence that leaves me only with CX or Antec VP series psus.

Btw do all the CX psus come with 5 years warranty in India?


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## gta5 (Dec 11, 2017)

quicky008 said:


> Thanks for the info.Although i am using a 750ti in this pc for now,i may upgrade to a better one in future such as a gtx 970(provided of course i can find one used at a reasonable price).Will the 450W CX psu be able to handle a gpu like the GTX 970?Can the increased load that will be exerted by a more power hungry gpu cause it to fail prematurely?
> 
> Is there any way to check which version of the CX psu i am gonna get before purchase(such as via some kind of serial/batch no etc)?I am thinking of swapping out my vs 450 with a newer one this week as i don't want to continue using it much longer.
> 
> Also how reliable are antec's VP 550V2 and VP650V2 psus?Antec claims that they have used "heavy duty" caps in these psus to improve their performance and reliability-are they similar to the CX series psus or even better than them?



unfortunately  you can't tell that which version you get from model no CP-xxxxx  , only batch/serial no , and that info is with Corsair which batch is from which OEM .. both versions have the same model no .. you can only tell by looking inside the PSU through fan grill , that means opening the box ...

check this
Post your latest Purchase

how much is it going to be used like gaming hours per day etc .. if it's not going to be too heavily used i think it should be fine with Gtx 970..

buy a new GPU after 6 months when VOLTA launches .,.. A GTX 2050TI will likely be very close to Gtx 970 performance and consume much less power...

ofcourse TXM is much better than seasonic and CX if you can afford it


Antec VP550P v2 and 650P are also good budget power supplies , until new Cx , they used to be the first choice in this budget .. but are now old..

they use all Japanese caps on 12v rail  and made by Delta , which is a very good and largest PSU maker ( makes server PSU's ) considered better than seasonic by most as on OEM   and if it weren't for the shorter warranty of only 2 years and older design , though high ripple on full load

but CWT's CX with many solid caps  seems better than VP550P/650P

but don't fall for that heavy duty marketing , they use that everywhere even in Vp450P which uses  100 % Capxon caps


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## chimera201 (Dec 11, 2017)

^ The part number is unique as far as i know. And it will be listed somewhere on the box most likely on the same sticker with the serial number/date of import. Besides it's easy to tell if it's the new ones or not by the 5 yrs warranty label. CX units are made by Great Wall and CXM (modular) ones are made by CWT.


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## quicky008 (Dec 11, 2017)

^^^At vedant computers(kolkata),CX 450 is retailing for 3350 and 550 for 4100-there's a difference of about Rs 800 between the 2.I wonder will it be worthwhile to get cx 550 by paying the extra amount or should i just stick to the 450W model-seems like a really tough choice!

I don't really game for long periods-maybe around 2-4 hours per day at the most (if at all).Will the Cx 450 hold up well under these conditions(when paired with a gpu like the gtx 970,that is)?

Thanks for offering your insights on the vp series psus-if they produce higher degree of ripple on full load then they are definitely a no-go.

@chimera:If a CX series psu bears the 5 yrs warranty label,then does it indicate CWT or great wall as its manufacturer?Which variant is actually the better of the 2-the one made by CWT or great wall?


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## gta5 (Dec 11, 2017)

chimera201 said:


> ^ The part number is unique as far as i know. And it will be listed somewhere on the box most likely on the same sticker with the serial number/date of import. Besides it's easy to tell if it's the new ones or not by the 5 yrs warranty label. CX units are made by Great Wall and CXM (modular) ones are made by CWT.



this is the thing .. new CX (non modular ) is made by both CWT and Great wall .. it is dual soured and hence the CP-xxxxx won't be able to tell ... both Cx 450 has Model no - CP-9020120

read jonnyguru's comment ..

What's the difference between the Corsair cx450m and the cx450?


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## chimera201 (Dec 11, 2017)

gta5 said:


> this is the thing .. new CX (non modular ) is made by both CWT and Great wall .. it is dual soured and hence the CP-xxxxx won't be able to tell ...
> 
> read jonnyguru's comment ..
> 
> What's the difference between the Corsair cx450m and the cx450?



Ah okay. Something that EVGA was doing but much worse. Great Wall is still ok though shouldn't be much of a quality difference between CWT and Great Wall. Corsair will still have to honour 5 yrs warranty in any case.


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## chimera201 (Dec 11, 2017)

quicky008 said:


> I don't really game for long periods-maybe around 2-4 hours per day at the most (if at all).Will the Cx 450 hold up well under these conditions(when paired with a gpu like the gtx 970,that is)?



Well if you are going to get a GTX 970 then you should just save up and get a TX550M. Even the old outdated Seasonic S12II is still a tier higher than the new CX.


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## gta5 (Dec 12, 2017)

chimera201 said:


> Ah okay. Something that EVGA was doing but much worse. Great Wall is still ok though shouldn't be much of a quality difference between CWT and Great Wall. Corsair will still have to honour 5 yrs warranty in any case.



Corsair HX, TX-M and CX finally go live on 80 Plus - jonnyGURU Forums

as per jonnyguru's comment .. lower efficient one is CWT on 80 plus list .. which has a number - RPS0053 , if you can find this on box .. then it can be distinguished .. Kartechnology has 1 , ask him if he can see this



chimera201 said:


> Well if you are going to get a GTX 970 then you should just save up and get a TX550M. Even the old outdated Seasonic S12II is still a tier higher than the new CX.



this is why tiers are subjective and only good as a starting point  .. decide based on reviews/ comparison.. and i think that tier list hasn't been properly updated yet less/no reviews maybe..  visit their forum instead there are recent long discussions regarding s12ii based on pros and cons vs other newly launched models

see this link of CWT made CX .. this is overall better than s12ii .. there are only like 2 main mediocre caps and rest all you see mostly are solid caps or jap caps  apart from those 2-3 tiny ones

S12ii is less safe and doesn't have even UVP on 12v rail , No OCP . no OTP , older design.. it only has advantage of fully jap cap and FDB fan

*club.dns-shop.ru/hardware/Обзор-и-тестирование-блока-питания-Corsair-CX650/


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## quicky008 (Dec 12, 2017)

@chimera:You are right.But according to johnnyguru's psu tier list,s12II bronze psus are at tier 3 whereas CX (2017 edition)models are at tier 4-so hopefully,the latter aren't too bad either.

Although i have mentioned that i may buy a 970,it was merely just speculation and i am not entirely sure if i will ever do that(the reason being that most people who own such gpus usually demand astronomical prices while selling them off,therefore finding one at a good price is really difficult nowadays).So if i get a low power demanding gpu instead like the 950/1050 etc,i suppose the CX 450 will be adequate for it,right?

@gta5:How do you manage to dig up these elusive reviews from foreign websites?
Thanks a lot for sharing it though-i was looking for a comprehensive review of a newer CX unit but couldn't find any-the few ones that are available are particularly for the modular variants of these psus.So i will definitely check it out!


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## gta5 (Dec 12, 2017)

quicky008 said:


> @chimera:You are right.But according to johnnyguru's psu tier list,s12II bronze psus are at tier 3 whereas CX (2017 edition)models are at tier 4-so hopefully,the latter aren't too bad either.
> 
> Although i have mentioned that i may buy a 970,it was merely just speculation and i am not entirely sure if i will ever do that(the reason being that most people who own such gpus usually demand astronomical prices while selling them off,therefore finding one at a good price is really difficult nowadays).So if i get a low power demanding gpu instead like the 950/1050 etc,i suppose the CX 450 will be adequate for it,right?
> 
> ...




with CWT version , with a 970 it should be fine for 4 years ( based on early limited info/pics )

with 970 your system would be consuming roughly around 300 watts or less .. get the Cx550 version then it will be less stressed .. but ofcourse if you can, try going for Corsair TXM at Rs 5700 from vedant by saving up after a month or 2

This Cx review was posted by someone else on jonnyguru's forum , That VS 450 review i came across after searching , when i was looking for a review  VS 450 CP-xxx96 model no.. probably the only one on web


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## quicky008 (Dec 13, 2017)

Bought cx 450 today but haven't used it yet-so it remains to be seen how its gonna perform....

Wanted to buy the cx 550 actually but ran out of cash,so had to settle for this unit-hope it wont disappoint.


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## gta5 (Dec 13, 2017)

quicky008 said:


> Bought cx 450 today but haven't used it yet-so it remains to be seen how its gonna perform....
> 
> Wanted to buy the cx 550 actually but ran out of cash,so had to settle for this unit-hope it wont disappoint.



congrats  , that was bought  fast while we were still discussing  ..


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## quicky008 (Dec 13, 2017)

i bought it so soon as i have been occasionally hearing strange "whirring" noises from within my pc that seem to be originating from my vs450-so i didn't want to risk using it much longer as i was afraid of what might happen if it decided to pop under heavy load and take the rest of the components with it!


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## quicky008 (Dec 13, 2017)

In fact my anxiety increased tenfold once i watched this:


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## quicky008 (Dec 13, 2017)

I have installed the new psu-however the results obtained with it seem even more disappointing than what i had anticipated-under load conditions the voltage on its 12v rail drops to around 11.6V,which is even lower than that of my VS450,and while idling it stays at around 11.95V.

Given that this a 80 plus bronze certified psu,this is rather odd to say the least.Is there any reason to be concerned about this?


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## chimera201 (Dec 13, 2017)

11.6V is bad. You checking with HWInfo? Check in bios for idle to be sure.


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## gta5 (Dec 13, 2017)

11.6v is really bad for a DC-DC  unit  and hence i don't think it is accurate at all , so ignore it

software readings are off many times , you can check in BIOS  but to be really sure you  need to test it with multimeter..


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## quicky008 (Dec 13, 2017)

Yes i used hwinfo.In bios it shows around 11.88V-is it safe to continue using this psu if it really is providing around 11.6V on the 12V rail under load?

heres a screenshot:
Untitled


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## gta5 (Dec 13, 2017)

yes it is safe alright ,  safe upto 11.4 v , but i highly doubt it actually is doing 11.6v under load ,  take your pc to a repair shop and ask him to test it under load with multimeter


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## chimera201 (Dec 13, 2017)

Isn't there someone else on the forum with a CX450? Could ask him how much he gets. Also are the cables properly plugged in?
Bios usually will be correct and since you already saw the results with VS450 then this is bad. If the voltage reporting was error prone on your mobo then VS450 should also had been lower as well.


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## quicky008 (Dec 13, 2017)

well,does it mean the unit may be defective/faulty?Can someone please provide the link to some tutorials where its shown how to test the 12v rail of psu without actually disconnecting it from the mobo?Can the 12 V readings be taken from any molex/pci-e connectors somehow?


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## gta5 (Dec 13, 2017)

BIOS might be usually correct , not always..

Power Supply FAQs

Corsair TX-850V2 on its way out? - jonnyGURU Forums

Why do motherboards suck at reading voltages? - jonnyGURU Forums


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## quicky008 (Dec 13, 2017)

^thanks for the links Gta5,i am seriously fed up with this voltage issue and just want to be able to use my computer without any further glitches or interruptions.Do you think its ok if i ignore the readings(which are supposed to be within ATX spec,even though they are low)and just continue using this psu?

are there any symptoms of system instability that can be observed when the voltages on 12V rail is too low or high?


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## gta5 (Dec 13, 2017)

quicky008 said:


> ^thanks for the links Gta5,i am seriously fed up with this voltage issue and just want to be able to use my computer without any further glitches or interruptions.Do you think its ok if i ignore the readings(which are supposed to be within ATX spec,even though they are low)and just continue using this psu?
> 
> are there any symptoms of system instability that can be observed when the voltages on 12V rail is too low or high?



yeah it's fine .. ignore those software readings  for now , but to make sure  you need a multimeter , no other way..


, take it to a PC repair shop and get it tested there on load for 15-20 minutes and all .. he'll take 50-100 Rs max

From what i know ,   if voltage gets low enough your system may become unstable..  if you have an Asus mobo your anti surge potection would likely kick in first...

but at low voltages , your components may draw more current in order to keep working at same level and that can be harmful..

At  dangerous levels PSU would/should shut down because Under voltage protection (UVP) and Over Voltage Protection(OVP) would kick in .. but it depends at what voltage levels the protections are set at and may vary from PSU to PSU.. without proper testing nothing can be known..

Can low power damage components? ( Mcsteel's reply )
jonnyGURU Forums - View Single Post -  UnderVoltage Protection (UVP)?

DC-DC PSU should not have such low readings..


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## quicky008 (Dec 14, 2017)

i will attempt to test it with a multimeter-but is it safe to carry out the test by taking readings from a molex connector while the 24pin atx connector is still attached to the mainboard?

I dont want to remove the 24pin connector again just for testing as doing so is very cumbersome and requires a lot of effort.Can you let me know the proper procedure to check the voltage on the 12v rail using this method?


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## quicky008 (Dec 14, 2017)

thanks,i will look into it.I have made a post on this issue at johnnyguru's forum.

Low voltage on the 12V rail in a brand new Cx450 - jonnyGURU Forums

lets see what they might have to say about this!


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## gta5 (Dec 14, 2017)

quicky008 said:


> i will attempt to test it with a multimeter-but is it safe to carry out the test by taking readings from a molex connector while the 24pin atx connector is still attached to the mainboard?
> 
> I dont want to remove the 24pin connector again just for testing as doing so is very cumbersome and requires a lot of effort.Can you let me know the proper procedure to check the voltage on the 12v rail using this method?



Take it PC shop get it tested for 50-100 Rs  there , it is better  than making a mistake because of inexperience and have a short somewhere or  risk getting shock..


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## chimera201 (Dec 14, 2017)

jonnyguru is basically asking for what i asked before:



chimera201 said:


> Also are the cables properly plugged in?


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## quicky008 (Dec 14, 2017)

yes,the cables seem to be plugged in securely from what i can see now-would it be prudent to remove and reseat it once again just to make sure?


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## chimera201 (Dec 14, 2017)

Yeah you should probably reattach the cables just to be sure. I have that B75M-D3H(v1.0) mobo at my native place. And with a Seasonic S12II it showed about 12.2V at idle and about 12V on load from what i remember. And both the mobo and PSU are 5+ years old.


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## quicky008 (Dec 14, 2017)

Well i too have a seasonic psu installed in another pc that has an asus mobo-its readings are just about the same as the ones reported by your gigabyte motherboard-around 12.1V at idle and 12v under load-in fact i have never seen it dip below 12v on any occasion.

Wish i had spent a bit more and bought a seasonic psu-their quality is fairly consistent and they seem far more dependable than other brands.I had a Corsair vx 450 earlier which was actually an OEM seasonic unit and it too was always very stable-never for once in the 5-6 years that i owned this psu did I face any problems with it.

I just hope my newly bought CX 450 doesn't turn out to be defective,as if it does then replacing it will be a very cumbersome affair.I think it will be difficult to make them realize the exact nature of this problem as most of the typical ill-informed personnel at service centers will automatically assume that the psu is fine as long as it remains operational-the fact that its outputting less than optimal voltages on the 12V rail will probably not make any difference to them.


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## quicky008 (Dec 15, 2017)

i was running out of patience,so i decided to test the psu today and i've got some rather surprising(or should i say shocking?!)results-i tested the 12v rail by connecting the leads of the multimeter to the 12v and ground wires of a spare molex connector-while the pc was idling,hwinfo displayed 11.95/11.88V whereas the reading on my multimeter was 12.27V,and when the pc was being subjected to load(i ran a couple of games and 3d mark benchmarks for a few minutes)hwinfo reported 11.73/11.66V whereas my multimeter gave a reading of 12.29-12.30V(the voltage seemed to have increased slightly rather than decrease,unlike what was being shown in hwinfo)!

So are the readings taken using the multimeter the real deal?If yes,then it can be safely concluded that hwinfo was reporting completely bogus and inaccurate values.Is there much of a discrepancy between the 12v output of a molex connector and the 12v that goes into the motherboard(via the 24 pin atx connector)?Are these voltages fairly similar to each other or can they differ to some extent?If not,then i suppose my psu is fine,right?

Here's are some photos i took while taking the readings using the multimeter:


idle reading 

load reading


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## bssunilreddy (Dec 15, 2017)

quicky008 said:


> I am currently using a corsair Vs450 psu on a build with the following specs:
> 
> Core i5,gigabyte B75 mobo,4+4=8 gb ram,3 HDDs,750ti gpu.
> 
> ...


Is 11.8V on 12V rail safe? - Components - Tom's Hardware


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## quicky008 (Dec 15, 2017)

^thanks,but i am already aware of it as i had started that thread myself on tomshardware a few days ago.


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## chimera201 (Dec 15, 2017)

Usually the voltage would go lower on load as could be seen in any professional PSU reviews.
e..g
*www.cybenetics.com/d/cybenetics_VUm.pdf

Probably some problem in how you measured it.


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## quicky008 (Dec 15, 2017)

What kind of problem could there be?Can you please elaborate on that?Was my multimeter giving incorrect readings?


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## gta5 (Dec 15, 2017)

see this is why these software values are totally unreliable in many cases

I think the important thing is on idle it is showing 12.27v , whereas on load it is 12.29/12.30v ..  so the  delta variation is  very small , this is good

as for getting 12.27v
if i  am not wrong , is your multimeter a generic one ?
check your multimeter for accuracy  , you also have a PC with Seasonic S12ii  , test it with that as well how does it fare there ? test it with some good laptop  charger .. how close  values do you get there .. ?

Cx450 is otherwise excellent as you can see from cybenetics report and the tested version there is the same version as yours RPS0053 ..


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## bssunilreddy (Dec 15, 2017)

Calculate your voltage drop using this Calculator: Voltage Drop Calculator


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## quicky008 (Dec 15, 2017)

@gta5:yes,on idle it was at 12.27v for the most part but occasionally dipped to 12.26v for a few secs.Do you think i would have got any sensible readings at all(let alone readings close to 12v)if i had done something wrong during the testing process?And yes,my multimeter is indeed a generic one.Are the more expensive multimeters usually more accurate than their generic counterparts?

I will test my seasonic psu as well and see how the multimeter holds up there-if it gives really weird readings then we can conclude that its probably acting up.

@bssunilreddy:thanks,i will check it out-but on first glance it appears a bit too technical(for a layman like me)and so i may not be able to figure out how to use it properly.


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## gta5 (Dec 15, 2017)

as far as i know

if it was something wrong during testing process .. the voltages would be a lot different ..

0.02-0.04v is very small variance , so it appears good

but you can retest it once more , to confirm

yes generic multimeters aren't that accurate , and their quality varies ... so this is my first guess  .. to confirm you will have to test it with seasonic s12ii / good laptop charger/some other device  how accurate is your multimeter

Rest , follow advice on jonnyguru forum , members there are far more experienced


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## quicky008 (Dec 15, 2017)

thanks for the suggestion.Do you think these types of mutimeters are likely to give better readings than the generic ones:

DT9205A Digital Multimeter LCD AC/DC Ammeter Resistance Capacitance Tester, | eBay

MAS830L Digital Handheld Multimeter Multitester White / Blue Backlight LCD | eBay

If yes,i just might buy one for further testing.


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## gta5 (Dec 16, 2017)

i don't know much about these  , you should ask this somebody else...

 good branded reliable multimeters are above 1500 rs  like Fluke 101 costs Rs 2300 .. while these quoted by you may be better than your current one's , i am not sure which one's actually are worthwhile  and value products for light/occasional uses..

you can have a look at amazon reviews .. and ask somebody  else on this/other forums before buying

*www.amazon.in/Mastech-MAS830L-Digital-Pocket-Multimeter/dp/B0093H048Y

and this thread may be of help

Cheap multimeters... what is so bad? - Page 1


to be really sure , take it to any local PC shop get your system tested there as well for 50-100 Rs , which is better and cheaper option if it's just a 1 time /occasional use case .. or maybe borrow from friend or something hopefully a different one

you will also get to know how much accurate your multimeter is..


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## quicky008 (Dec 16, 2017)

True,but the thing is no one i know possesses an expensive or state of the art multimeter-almost everyone uses these generic multimeters these days to perform routine electrical tests,and that also includes the local pc repair guys.

btw i tested the output of a generic power adapter that i use with my modem yesterday-its rated output is 5.2v dc and the reading that i got on my multimeter was 5.5v.Also i tested a new cr2032 battery that i had lying around which gave a reading of 3.3v-does that give you any idea about the accuracy of this meter?

I will also attempt to test my s12ii psu shortly.

(ps according to the manual of my dt830d multimeter,the accuracy of DC voltage readings for 20V range(and "resolution" of 10mV) is +- 0.5%+3 -what does it actually mean?)


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## gta5 (Dec 17, 2017)

these cheap 150rs    meters  are reasonably accurate upto 5volts  .. when measuring 10-12v+ they can be  off.. but 5.50v on 5.20v output looks high 

well your pc shop guy may not have the expensive one but likely to have a better  model than yours   and   calibrated  so you may get a good  rough estimate idea of readings...

that range determines how far off they can be , but i doubt specs on these 830 units mean much at all.

Digital Multimeter Accuracy Explained | brianhoskins.uk


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## quicky008 (Dec 21, 2017)

thanks once again for the exhaustive set of reviews,gta 5-yesterday i finally got around to testing my seasonic s12II psu using the very same multimeter-on idle it gave a reading between 12.55-12.56V and on load it stayed between 12.51-12.52V(it actually seemed to decrease,unlike what i experienced with my corsair psu).The readings were taken from a spare molex connector like before.

However on that pc,hwmonitor didn't seem to recognize the onboard h/w monitoring chip in the asus mobo that was being used and so it kept giving all kinds of weird and incoherent readings(along the lines of V1,v2 etc which made no sense)-so i used asus aisuite to monitor the voltages while taking the readings using the aforesaid meter-on idle it was around 12.096v and on load it dropped slightly to 12.00V.

So the difference between the readings taken using 2 different methods amounts to around 0.50V approximately-it seems the software readings were inaccurate once again by a considerable margin,isn't it?


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## gta5 (Dec 21, 2017)

from the description ..

my guess is your multimeter is off  on the higher side .. i.e showing between 0.20-0.25v extra than actual ..

your multimeter was also showing 5.50v at 5.20v rated charger , to confirm you can test  the power brick/adapter of laptop or tv or monitor or some other devices and see their outputs they are likely to report 0.20-.25v higher as well

CX450 - idle - 12.27 v
S12II - idle- 12.55v

so in actual , my guess is  CX 450 is somewhere around 12.05-12.10v  and S12II is around 12.30 v on idle

and this is inline with the reviews as..

In this review - CX 450 
Cx 450 at   45 watts shows 12.05V

in this review  at 50 watts S12ii is 12.25v

in this  review  at 140 watts S12ii is 12.37v   ...

in this  review  at 200 watts S12ii is 12.35v approx  ...

So your unit is likely showing excellent results as shown in that CX450 review.. and at idle the actual voltage is between 12.05-12.10v , and on load the variation is only 0.02-0.04v , which is the important part , same case with S12ii around 0.04-0.05v variation .. and S12ii is also one of the best group regulated designs with crossloading .. so there is not such a big variation on loads upto 200 watts ( what GPU was their in seasonic system ? - likely not too much power hungry )

with VS450 you are likely to see much bigger variance on load


and ignore the AI suite/BIOS/software readings

  Unstable 12v on Super Flower psu - jonnyGURU Forums


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## quicky008 (Dec 21, 2017)

The gpu on the system with the seasonic psu was a gtx 960-it requires an additional 8pin power connector but i dont think its very power hungry.

Yes,it seems that the multimeter is reporting slightly higher voltages than normal-unfortunately i dont have too many other working dc adaptors/power bricks etc at hand for further testing and so i cant confirm this atm.But if i can procure another higher quality multimeter then hopefully i will be able to check and compare the readings between the 2 and ascertain whats really happening.


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## gta5 (Dec 21, 2017)

yeah another meter would really confirm , but  i think it is highly likely now that your CX 450 is good..  and doesn't have any defect


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## quicky008 (Dec 21, 2017)

thanks,btw in jonnyguru's review(and also in cybernetics' review of cx 450),he referred to some tests as CL1 and CL2-do you have any idea as to what this actually means?


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## gta5 (Dec 21, 2017)

CL is Crossload tests , there are 2 tests in most reviews , 1st in which 3.3v and 5v rails are heavily loaded and 12v rail is very lightly loaded.. this is unrealistic for most actual setups

second one is most important , in this 12v rail is heavily loaded , and 3.3v and 5v rail is very lightly loaded .. CPU and GPU draw power from 12v , so this is very realistic in any system , 3.3v is rarely or very lightly used these days and 5v is lightly-moderately used  ( hard drive , USB,  chipset etc )

group regulated units don't behave well when one rail is heavily loaded and other rails only lightly loaded


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## quicky008 (Dec 21, 2017)

That's good to know,please note that i actually have the 620w variant of the seasonic s12ii and its the newer revision thats been featured in the second review(the one with flat cables and a stamped fan mesh).

But hopefully their designs are not that different and therefore i think its safe to assume that performances of the 520w and the 620w units will be pretty similar to each other.


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## gta5 (Dec 21, 2017)

the 620 watt version performs better than 520 version.. it is at 12.13v at 200 watts vs 12.31v for 520 watt version acc to this review

Hardware.Info Nederland

and 12.24v at 140 watts for 620w vs 12.37v for 520 watt version in this review

Обзор и тестирование блока питания Seasonic S12II-620 Bronze

another meter is required to finally confirm , hopefully atleast a different type/model than DT-830d .. or take it to pc shop


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## quicky008 (Dec 26, 2017)

A friend of mine has a mastech mas830 multimeter-do you think it would be suitable for testing my psu?on the product page for this psu on amazon the reviews in general seem pretty favourable.

Also i was going through the cybernetic's test report for cx 450 that you had referred to earlier-it seems this test was based on the unit that's produced by great wall,have they also tested the one produced by CWT?If yes,could you please post a link to the download page for its test report?


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## gta5 (Dec 26, 2017)

quicky008 said:


> A friend of mine has a mastech mas830 multimeter-do you think it would be suitable for testing my psu?on the product page for this psu on amazon the reviews in general seem pretty favourable.
> 
> Also i was going through the cybernetic's test report for cx 450 that you had referred to earlier-it seems this test was based on the unit that's produced by great wall,have they also tested the one produced by CWT?If yes,could you please post a link to the download page for its test report?



yeah mastech appears to be  decent

 scroll down to the bottom of that report , you will see a pic of that PSU with no -  RPS0053 ,your's is 0053 so that is the same one that has been tested


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## quicky008 (Dec 26, 2017)

hmm if thats the case then does it mean that mine was built by Great wall and not CWT as we had assumed earlier?Do the CWT made cx 450s have a different product code?


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## gta5 (Dec 26, 2017)

quicky008 said:


> hmm if thats the case then does it mean that mine was built by Great wall and not CWT as we had assumed earlier?Do the CWT made cx 450s have a different product code?



that would require  clear pics showing internals through fan to  reasonably get a good idea.. , your appears to be CWT based on early info

The other OEM's Code is RPS0063  - click on it

this is  RPS0053


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## quicky008 (Jan 2, 2018)

gta5 said:


> yeah another meter would really confirm , but  i think it is highly likely now that your CX 450 is good..  and doesn't have any defect


I finally obtained a mastech meter today and tested my psu once again,but the results were really disappointing!
During idle,the voltage reading from a spare molex connector was around 11.72V and during load it increased slightly to about 11.76V

I also tested the pcie connector of this psu-during idle it was around 11.67-11.68v and on load it increased to around 11.71V.Hwinfo as usual gave a reading of 11.88v on idle and 11.66v on load.

To ensure that this new meter was not giving erroneous readings,i tested a spare molex connector of my seasonic psu and surprisingly its voltage on the 12v rail never dipped below 12v-on idle it was around 12.07V and during load it varied between 12.05-12.06v approximately.Hopefully this establishes that the meter isn't at fault here.

It seems the readings that were taken previously using my generic dt830d meter were off by a considerable margin(like you had predicted).

So does it mean that my cx 450 is defective?If the reports provided by cybernetics are anything to go by,a good CX 450 isn't supposed to output such low voltages-even under higher loads the voltage on the 12v rail of this psu didn't go below 11.9v in their tests.

If its indeed defective,the ideal course of action would be to rma it-however its likely to take quite a long time and there's no guarantee that the replacement unit would also not exhibit similar behaviour.Therefore would it be a good idea to ditch this psu altogether and get a newer,better one instead?Someone i know is interested in buying this psu and he's likely to give me around 2500 for it-do you think this is a good deal?

Also which psu would you recommend as its replacement?Even though its likely to leave huge hole in my pocket,i dont want to go for a cheaper unit this time around.Corsair's TX550m and 650m are available for around 5600 and 6400 respectively but i am rather wary of going for corsair again after this bitter experience with 2 of their psus(Vs 450 that i had earlier and my current cx 450).Or should i just purchase a seasonic s12ii psu instead(as my experience with my seasonic psu has so far been positive).Please advice.


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## gta5 (Jan 2, 2018)

quicky008 said:


> I finally obtained a mastech meter today and tested my psu once again,but the results were really disappointing!
> During idle,the voltage reading from a spare molex connector was around 11.72V and during load it increased slightly to about 11.76V
> 
> I also tested the pcie connector of this psu-during idle it was around 11.67-11.68v and on load it increased to around 11.71V.Hwinfo as usual gave a reading of 11.88v on idle and 11.66v on load.
> ...



hmm..

well if your meter was showing 11.72v on idle with CX450 , then it will show around 12.03v with seasonic , because with your previous meter it was 12.27 with cx 450 and 12.55v with seasonic on idle, so the difference between seasonic and cx 450 is 0.30v  , this result  was expected if CX 450 showed 11.72v

but this still doesn't tell us whether your mastech meter is accurate or not .. say for example if your mastech meter is under-reporting then  CX 450 could well be outputting 11.90v and then Seasonic may be outputting 12.20v  on idle (, in most seasonic reviews that i saw of 620 watt version , at idle the voltages are in 12.15-12.20 range .. so 11.85-11.90v for CX 450 is not bad )

to need to confirm it's accuracy you need to test other devices .. you have your modem adapter right that showed 5.5 on 5.2v rating ,test that as a start..
but you need to test a few more devices with higher voltage output like  12v , 20v output .. because at 5v these meters may still not be that off the mark

check with laptop charger of your friend , adapter of your  monitor or your TV  ?

even my airtel set top box adapter is rated for 12v .. check yours

test with atleast 3 different devices

only then you will get a good rough idea if this meter is also off or not.. or off by how much ?  these meters tend to go out of calibration

coming to CX 450

we have 2 tests of your same exact PSU , one by Cybenetics and 1 by 80 plus ( that i linked in previous post ) where it shows excellent voltage regulation ( although 80 plus doesn't have crossload tests ) and in addition also that CWT made Cx 650 review that i linked arlier

so yours has to be a slightly defective piece to have such voltages

Let's just assume even if your  Cx 450 is showing 11.70v , while these results are not good  but they aren't dangerous either that you need to buy another power supply entirely .. ATX specs allow for upto 11.40v .. so even 11.45v is not harmful  for hardware .. RMA'ing would be good as it is free but buying entirely different power supply is just totally unnecessary

the most important part is the change in voltages on load , with VS450 i am pretty sure you would have noticed a way bigger drop than CX 450

also please post 3-4 clear pics of your PSU through fan showing as many internals at different angles..


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## quicky008 (Jan 2, 2018)

Thanks so much for your response,yes i too have a airtel dth stb at home and a couple of other devices as well that are powered by dc adapters-let me check them and i will post my findings shortly.

The reason i want to move on from this psu is that i am really fed up with this repeated testing and retesting which doesn't seem to provide any conclusive or fruitful results.Are Corsair's new gold certified TXM psus better than these CX psus?


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## quicky008 (Jan 11, 2018)

here are some closeups of my CX 450:

single large capacitor

view of transformer

From its physical appearance,it appears to be a cwt made unit.


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## gta5 (Jan 11, 2018)

yup , it appears to be CWT


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