Does all memory need to be in matched pairs?

[cdh123]

Hi, I have a question about memory for my first time build. I will be using 32 bit OSs and I want to get DDR3 memory to go with my fancy new mobo. As you all know, this memory is expensive so I only want to get what I can actually use. I have read in various places that with either XP or Vista (I?m going to dual-boot) the OS can only read 3GB.

What would be the best way to do this? I think I heard somewhere that one must install memory in matched pairs or something. Is this true? Would I need to get a 2 GB (2x 1GB) kit and a 1 GB (512 x 2) kit to do this right? Or could I just get a 2GB kit and a single 1GB stick and rock with that? I?ll put the mobo and the memory that I want to use. I?d appreciate any advice on the best memory configuration to use with this mobo. Thank you.

Mobo: http://www.newegg.com/product/...x?item=N82E16813131235

2 x 1 GB kit: http://www.newegg.com/product/...x?item=N82E16820145183

EDIT: Also, I forgot to ask: If I got that memory in the link, would I have to (or want to) get only PC3 10600 in the additional 1 GB? Or could I get like PC2 10400? I only ask because Newegg doesn't seem to have a 2 x 512 of PC3 10600. Thanks again!

 

[Yellowbeard]

You are not going to find any 512mb modules of DDR3 AFAIK. Most if not all of the ICs used for DDR3 are 128mb and no desktop memory uses a by 4 arrangement, or 4 x 512mb ICs. A single matching module of what you listed should work just fine for 3gb. However, I am not aware of it being sold as singles as there is virtually no demand for single modules these days. You may need to buy 4 modules or, ideally just buy a 2 x 2gb kit which is easier to tune and less load on your memory controller.

 

[cdh123]

Good stuff! Thanks very much for your answer

 

[imported_BikeDude]

Originally posted by: cdh123
What would be the best way to do this? I think I heard somewhere that one must install memory in matched pairs or something. Is this true?

Matched memory has been with us for years, but I've yet to utilize any.

I do know there are differences (or used to be) between memory modules. The number of layers in the PCB was one major difference at one point.

But matching memory modules? Somehow the factory will pick two modules from the same batch, "match" them (what, is the factory doubling as a dating service?) and decides they will work better as a team for your motherboard, rather than risk having to spend the rest of their life with, say, two other modules produced the next day or something...

I'm sorry, but I strongly suspect matched memory is a ploy to make sure you do not purchase stick #2 from a competitor. However, I would not be surprised if the more expensive modules have actually been tested. Meaning they won't crap out as soon as you sink memtest86 into them.

I am dimly aware that strange things happens at big transfer speeds. Cat-5e cables are twisted in a certain way to avoid cross-talk. Fine. Maybe there is something to matched memory sticks, but somehow... I somehow believe you'd have to match them to a particular motherboard & CPU as well in that case. ( & PSU & whatever components draw power from the PSU & so on)

But these are my guesses. FWIW, I've been wanting to ask the same question myself for a while.

 

[Yellowbeard]

I somehow believe you'd have to match them to a particular motherboard & CPU as well in that case. ( & PSU & whatever components draw power from the PSU & so on)

But these are my guesses. FWIW, I've been wanting to ask the same question myself for a while.

We hand test them and package them immediately after testing. We run them in a dual channel MOBO and verify that they operate together. The matching memory (aka dual channel) is a spec set forth by MOBO makers due to limitations of memory controllers in a dual channel environment. This was not invented by the memory industry nor is it a ploy, marketing or otherwise. We are simply supplying what the MOBO industry mandates. So, rather than assume memory from the same batch will work, we test it together.

 

[imported_BikeDude]

Fair enough, but what is done with the modules not passing the test?

Or for that matter: Do you keep testing modules together until two are found to match?

 

[Yellowbeard]

Modules that don't run stable at a given speed can be retested to see if they are stable at a lower speed and thus sold as such.

And, for matched pairs in our TwinX kits, yes, we test them make sure every packaged pair runs together stable, at spec, in a dual channel MOBO.

 

[imported_BikeDude]

A couple of things... IIRC, the memtest86 documentation states that not all CPUs are equal. Memory that pass all tests with a Intel CPU could fail certain tests given an Athlon CPU (this was early P4, pre-Athlon64 days).

Given your description, I get the impression that you guys test using a single CPU in one particular motherboard?

I tend to believe that chipset quality and the quality of the tracings on the motherboard is of bigger importance here than matching pairs of DIMMs? (I once had a poor quality epox motherboard that didn't run stable despite the expensive pair of matched DIMMs I put in)

It is nice that DIMMs are tested -- it hopefully saves me time and agony.

But, I suspect most configurations sold today are dual channel. Yet I can easily find unmatched single DIMMs in my local webshop.

Are the DIMMs binned to lower speed because they are poor quality, or because a "match" couldn't be found? Why aren't they sold/marketed as high-speed single channel memory? Were they verified to run successfully in single channel configurations before attempting to match them for dual channel?

 

[Foxery]

We hand test them and package them immediately after testing. We run them in a dual channel MOBO and verify that they operate together.

Sorry to nitpick, but surely there's a large, specialized testing machine at the factory? Plugging in thousands by hand to a real computer would require an inordinate amount of time.

As far as matching goes, it does rule out a lot of possibilities for compatibility problems. I did run into trouble a few years back where I tried two RAM sticks with either different density, or number of chips on the PCB, and my motherboard couldn't address them properly. The machine would boot into Windows, then crash immediately when I launched anything which required using memory space on the 2nd stick. Took me all week to realize why and swap them out.

 

[NinjaJedi]

Originally posted by: Foxery

We hand test them and package them immediately after testing. We run them in a dual channel MOBO and verify that they operate together.

Sorry to nitpick, but surely there's a large, specialized testing machine at the factory? Plugging in thousands by hand to a real computer would require an inordinate amount of time.

As far as matching goes, it does rule out a lot of possibilities for compatibility problems. I did run into trouble a few years back where I tried two RAM sticks with either different density, or number of chips on the PCB, and my motherboard couldn't address them properly. The machine would boot into Windows, then crash immediately when I launched anything which required using memory space on the 2nd stick. Took me all week to realize why and swap them out.

Here is a review on corsairs facility. I've linked the page on testing. I guess if they were dumb enough to use just one PC then it would take a long time.

http://www.hardwaresecrets.com/article/166/4

 

[Foxery]

Obviously not *one*, but I was still picturing a custom-made machine with a single purpose, not a real PC which takes the time to boot Windows! Interesting...

Thanks for the link

 

[NinjaJedi]

Originally posted by: Foxery
Obviously not *one*, but I was still picturing a custom-made machine with a single purpose, not a real PC which takes the time to boot Windows! Interesting...

Thanks for the link

No prob. I don't think a PC has to boot into windows to check if the sticks work. (together or not) Maybe they use memtest or something similar. Not all PCs use windows.

 

[Yellowbeard]

We have multiple testing stations and we also test on both AMD and Intel platforms. Among other things, we use tools and diagnostics from this source: http://www.uxd.com/rstpro2.shtml