# whats the real difference between RAM kits and single RAM stick.?



## khmadhu (Mar 25, 2011)

Hi,

As some of you know, I am planning to buy a new system,*www.thinkdigit.com/forum/pc-components-configurations/136936-finally-upgrading-9-year-old-pc-suggestion-required-very-custom-config.html and my config is ready,  but confused in buying new RAM.

Currently My requirement is 4GB RAM. so if I go for 1x4GB stick, will this give same performance as 2x2 GB RAM kits..? I know the 2x2 GB stick uses dual channel,and 1x4GB stick don't uses dual channel

is dual channel really for 2x2  only, or  can I do like below.

(Example)
*if I buy a 1x4GB stick now and  add another 1x4GB with same frequency and latency after 6 months. can I use dual channel between 1x4 and 1x4 then.?*

so, whats the real difference in buying RAM kits and single RAM stick.?
please provide some technical info also as it might help other users..


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## Zangetsu (Mar 25, 2011)

khmadhu said:


> *if I buy a 1x4GB stick now and  add another 1x4GB with same frequency and latency after 6 months. can I use dual channel between 1x4 and 1x4 then.?*


Yes u can use Dual Channel mode with two 4GB sticks....just put them both in odd or even slots 



khmadhu said:


> so, whats the real difference between RAM kits and single RAM stick.?



RAM kits have cooler attached to them...where as single RAM doesnt come with cooler....


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## asingh (Mar 25, 2011)

RAM KIT =

Dual Channel : Two identical DIMMs are sold with same speed, density, and timings.
Tri Channel : Thre identical DIMMs are sold with same speed, density, and timings.

This we you insure you get multi channel throughput.


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## khmadhu (Mar 25, 2011)

@Zangetsu


> just put them both in odd or even slots



is that mandatory to get dual channel. ?

Also I would like to know the best timings to set in BIOS for  DDR3 1600 Mhz RAM.
specifically Gskill Ripjaws  4x2 GB RAM 1600Mhz in  DP67BG mobo.


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## Piyush (Mar 25, 2011)

wait a minute

to use dual/triple channel ,do we have to place our rams in same slots?
i mean either even or odd...
o   e   o  e     o-odd,e-even
1   2   3  4

^^ thats what it means?


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## asingh (Mar 25, 2011)

^^
It depends how the board wants it. The manual tells that.


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## MegaMind (Mar 25, 2011)

^^ Usually color of DIMMs shows that...


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## Zangetsu (Mar 25, 2011)

khmadhu said:


> @Zangetsu
> is that mandatory to get dual channel. ?



most of the motherboards follow dat even/odd pattern to get Dual Channel.


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## asingh (Mar 25, 2011)

^^
AMD does not.


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## topgear (Mar 26, 2011)

^^ yep - in AMD mobos configuring ram modules for dual channel is so easy - just put two dimms in same colored slot and they are placed on the mobo side by side.

@ *OP*



> Currently My requirement is 4GB RAM. so if I go for 1x4GB stick, will this give same performance as 2x2 GB RAM kits..? I know the 2x2 GB stick uses dual channel,and 1x4GB stick don't uses dual channel



if you go for single 4GB ram module you wo't get same performance as 2x2GB sticks - performance will be a little but lower.



> is dual channel really for 2x2 only, or can I do like below.
> (Example)
> if I buy a 1x4GB stick now and add another 1x4GB with same frequency and latency after 6 months. can I use dual channel between 1x4 and 1x4 then.?



if you buy a single 4GB module now and add another 4GB module later with same speed and latency you will get dual channel.



> so, whats the real difference in buying RAM kits and single RAM stick.?



Ram Kits : = ensures two ( or three ) mem modules of same speed, latency, timings and batch were p[acked and tested together at the time of manufacturing.

Single Ram Stick - Say you buy a single ram stick now of A1 revision and when at a later time you want to buy another ram stick of same speed and company ( this can even happen if you buy two ram stick at the same time )  you may not get A1 rev hence the timings of the two mem modules may a bit different - though this may not happen always there are chances that this can happen anyway.

Ram kits *ensures* you have perfectly matched ram modules packed together at the time of packaging so there's no chance of speed, latency, timing or revision mismatch - this offers you complete peace of mind


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## khmadhu (Mar 26, 2011)

@topgear, 
Thanks for the detailed info.. 

BTW

Also I would like to know the best timings to set in BIOS for DDR3 1600 Mhz RAM.
specifically Gskill Ripjaws 4x2 GB RAM 1600Mhz in DP67BG mobo.


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## bhushan2k (Mar 26, 2011)

btw, windows 32-bit os doesn't support 4 or more than 4 gb memory as it is specified on every motherboard manufacture's site..it shows 3 or less than 3 gb memory always coz of addresses allocations limitations i guess..so they suggest to install 64-bit os..does than mean every 32-bit os doesn't support d same concept?? probly linux??


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## khmadhu (Mar 26, 2011)

bhushan05d251 said:


> btw, windows 32-bit os doesn't support 4 or more than 4 gb memory as it is specified on every motherboard manufacture's site..it shows 3 or less than 3 gb memory always coz of addresses allocations limitations i guess..so they suggest to install 64-bit os..does than mean every 32-bit os doesn't support d same concept?? probly linux??




Thats not true..  a 32bit linux can be configured to use upto 64GB of RAM!.
for this you need to compile the kernel with PAE(physical address extension).

the default is <4GB limit because, those days not that many people were using systems with memory above 4GB.

also 64Bit Linux is generally a little faster than 32Bit Linux, it
eliminates the per process memory limit(2 GB /process).


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## Zangetsu (Mar 27, 2011)

bhushan05d251 said:


> btw, windows 32-bit os doesn't support 4 or more than 4 gb memory as it is specified on every motherboard manufacture's site..it shows 3 or less than 3 gb memory always coz of addresses allocations limitations i guess..so they suggest to install 64-bit os..does than mean every 32-bit os doesn't support d same concept?? probly linux??



Even I believe  in this theory..but one of my frnd bought a HP ProBook
with windows 7 32bit & he says in system properties its showing 4GB RAM????


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## coderunknown (Mar 27, 2011)

^^ shows 4Gb but states 3.25Gb as usable.

*i54.tinypic.com/rhsi1v.jpg


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## bhushan2k (Mar 27, 2011)

tht's what i said..u can install any amount of ram upto maximum..bt ur 32-bit os shows less than 4 gb coz of os' limitations..


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## YatharthRai (Mar 27, 2011)

Simple reason:-
Single RAM Chip:-a single chip of 4GB 1600MHz.
RAM Kit:-dual chips of 2 GB 1333MHz

What will you buy? 
Certainly the RAM Kit because there are 2 Chips of 2 GB providing 2666 MHz of Speed whereas a single chip is providing only 1600MHz of speed.

@topgear:-He is right too, I got my computer with 512MB by Transcend  Ram, one stick only, It was faster but bought another chip of 512MB Ram by Samsung, both had different latency and my comp was a little slower. RAM Kit is better.


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## topgear (Mar 28, 2011)

khmadhu said:


> @topgear,
> Thanks for the detailed info..
> 
> BTW
> ...



you're welcome buddy 

The mobo will ( most of time ) automatically configure the correct/optimal timings of ram modules - if it is not then post it here and we will discuss about it.



bhushan05d251 said:


> btw, windows 32-bit os doesn't support 4 or more than 4 gb memory as it is specified on every motherboard manufacture's site..it shows 3 or less than 3 gb memory always coz of addresses allocations limitations i guess..so they suggest to install 64-bit os..does than mean every 32-bit os doesn't support d same concept?? probly linux??





bhushan05d251 said:


> tht's what i said..u can install any amount of ram upto maximum..bt ur 32-bit os shows less than 4 gb coz of os' limitations..



32 bit consumer grade OS has limitation but it's not a limitation of all 32 bit OS. a 32 bit OS can address upto 64GB of ram. for eg. Windows Server 2008 Enterprise x86 ( 32 bit ) Edition supports upto 64GB of Ram.



YatharthRai said:


> Simple reason:-
> Single RAM Chip:-a single chip of 4GB 1600MHz.
> RAM Kit:-dual chips of 2 GB 1333MHz
> 
> ...



Dual channel kit does not doubles up the frequency speed but what you get is a increment in bus width - single channel mem works at 64 bit bus width but dual channel works at 128 bit bus width by using two 64-bit data channels at the same time.


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## asingh (Mar 28, 2011)

Basically the cars run at the same speed, but the highway is broader -- so over all more traffic passes. Throughput goes up.


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## Piyush (Mar 28, 2011)

is there any utility s/w by which i can check the latencies of my ram without unplugging them up?


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## asingh (Mar 28, 2011)

The memory tab in CPU-Z shows what timings the RAM is running at. SPD shows the available timings with the respective voltages.


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## bhushan2k (Mar 29, 2011)

topgear said:


> 32 bit consumer grade OS has limitation but it's not a limitation of all 32 bit OS. a 32 bit OS can address upto 64GB of ram. for eg. Windows Server 2008 Enterprise x86 ( 32 bit ) Edition supports upto 64GB of Ram.


yup..server editions support more as the system based on server demands more and stable output..so the need is big..but my question remains..what about linux desktop editions (both x86 n x64)..will they support more than 4GB of main memory??



topgear said:


> Dual channel kit does not doubles up the frequency speed but what you get is a increment in bus width - single channel mem works at 64 bit bus width but dual channel works at 128 bit bus width by using two 64-bit data channels at the same time.



true..it is just like one stick takes a load of other one..so better throughput than single channel..



khmadhu said:


> for this you need to compile the kernel with PAE(physical address extension).


it possible then how?? is it possible for client users who downloads and installs linux distro or talking about at the time of making os flavour..??


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## topgear (Mar 29, 2011)

I'm not a linux expert ( or a user anymore ) though I've at-least 3 years of experience with it and once I've tried a live disc of a x86 edition of linpus ( later installed fedora and opensuse but the resut was same anyway ) linux and it was unable to recognize all 4GB mem - so by default linux x86 editions don't support ( let you use ) all 4GB mem.

Now coming to the PAE part - that will configure the kernel to address upto 16GB ram ( like windows server editions ) but that's complicated process anyway - either you have to get a PAE version of the linux ( distro ) kernel you are using or you will have to recompile the kernel by yourself - which not many users can able to do.

So the best way is to get a 64 bit version of your favorite linux distro and that will let you use all the ram


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