# What is the difference between a costly PSU and a normal SMPS?



## ajai5777 (Mar 23, 2010)

It may be a dumb question but what exactly is the differnce when even the wattage is same?
In my 5yr old PC it was frontech 400W smps.It had no stability issues even with power hungry p4 3ghz ,sound card ,tv tuner card,dvd rw,2 HDD's and 9500GT.

For my current config i planned a premium PSU.Later i thought that new proccy and new HW are not power hungry also i wasnt going to upgrade my graphics card from 9500GT which doesnt need a 6 pin power connector.So i went for Zebronics 450 W sata plus for just 500 bucks.As expected no problems for the new config.In both config i used an APC UPS.

Now i think its better to change the PSU when i go for a graphic card upgrade.

But actually what is the point to go for a 2k PSU in mid range PC's when .5k SMPS are available?


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## coderunknown (Mar 23, 2010)

ajai5777 said:


> It may be a dumb question but what exactly is the differnce when even the wattage is same?
> In my 5yr old PC it was frontech 400W smps.It had no stability issues even with power hungry p4 3ghz ,sound card ,tv tuner card,dvd rw,2 HDD's and 9500GT.
> 
> For my current config i planned a premium PSU.Later i thought that new proccy and new HW are not power hungry also i wasnt going to upgrade my graphics card from 9500GT which doesnt need a 6 pin power connector.So i went for Zebronics 450 W sata plus for just 500 bucks.As expected no problems for the new config.In both config i used an APC UPS.
> ...



its not a dumb question at all. many many times members here ask why can't a simple home pc run on a cheap psu if high end parts not used.

well if the setup is very simple, without graphics card (or even if there is, something very basic). non OC proccy, & all. a 400W or even 500W local psu is enough. but the thing is that they not reliable at all. they use to get damage very easily. little fluctuation & PSUs dead. & moreover they many times not get damage alone, but along with HDD or motherboard. & specially Optical medias (DVD writer). 

so if someone is purchasing a pc on a tight budget he/she may go along with the bundled default PSU but i always request buyers to get something better if budget permits. PSU like VIP, PowerSafe or Zebronics Pro good enough for simple setups. however if midrange graphics + OC is included a sub 3k, 80+ certified PSU from some reputed international manufacturer best combo.

well in your case, its good. your graphics card is very less power hungry. proccy will eat up somewhat amount of power. but the main thing you missed is when a board gets old, the caps slowly dry up (all old boards ships with electrolyte caps) & the power consumption subsequently rises up.


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## ajai5777 (Mar 23, 2010)

Sam.Shab said:


> They use to get damage very easily. little fluctuation & PSUs dead.



But its run from a decent UPS.So there wont be much fluctuations.
Now i need to get atleast 9k for a graphics card upgrade+PSU.Hope I'll get something from 9500GT.


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## Piyush (Mar 23, 2010)

ajai5777 said:


> It may be a dumb question but what exactly is the differnce when even the wattage is same?
> In my 5yr old PC it was frontech 400W smps.It had no stability issues even with power hungry p4 3ghz ,sound card ,tv tuner card,dvd rw,2 HDD's and 9500GT.
> 
> For my current config i planned a premium PSU.Later i thought that new proccy and new HW are not power hungry also i wasnt going to upgrade my graphics card from 9500GT which doesnt need a 6 pin power connector.So i went for Zebronics 450 W sata plus for just 500 bucks.As expected no problems for the new config.In both config i used an APC UPS.
> ...



hey its not a dumb question
good that u at least asked that 
most guys dont know actually (they prefer to go for cheapest brand possible)
even i was not aware of the different brands and their different series

rest of the info has been given to u by sam.shab


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## asingh (Mar 23, 2010)

Take it this way.

A high grade PSU (read not wattage rating, but good manufacturer),  is tested and certified to provide clean ripple free power at various loads and specific temperatures. Give *this* a read. When power hungry components are mounted to a system (GPU/OC profiles), a lot of power is drawn constantly from the mains and pre converted to DC by the PSU. Good PSUs insure it is spike free, and as per the rail rating -- supply is pushed out. A bad PSU propagates directly to the system. It will slowly cause system damage. The worst part is, you hardly get a warning, there is no fail safe mechanism. Plus a good PSU is efficient. 80+ efficiency translates to: 320W used by the system : 400W pulled from mains. It is the ratio of output to input. A good rated PSU insures this too.

So invest in a good PSU.


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## acewin (Mar 24, 2010)

same difference you may think in cheap earphones available in less than 100 bucks and cheapest of original sony earphones.
and as asigh said, a cheap PSU will have efficiency even less than 70%, and the level of stress that they can take is even lesser. this stress is not just voltage fluctuation. you should remember system draws power as per its reqs which can vary from 300W in low-utilization to 500W in max load, cheap PSUs are not good for this kind of stress.


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## VarDOS (Mar 24, 2010)

@ajai 
i was too thinking the same, but after some of the members here and on IRC explained me all.

A PSU does not have only Power but also efficiency, as said up 80+ Certified PSU is always good. It has 80+ Efficiency.

Also check your current PSU, on it there will be a table of power consumption, just check the Current on 12V rail. It will be 13A - 16A which is very low and comes only with the Local PSU. In a branded PSU, the current on 12V rail is more than 30A which is good for many power Hungry cards like GTS250 (in my case).


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