I'm sure this is on google or answered in another thread in TT somewhere, but I'm also looking at real world opinions and futureproofing. DDR2 is at the floor right now and I need to make a large order.

If you had about 75 computers that you wanted to upgrade all currently running WinXP 32bit and a mixture of some with only 2 DIMM slots and some with 4 slots; how would you place this order?

- 2GB in all machines running dual channel (1GBx2)
- 2GB in all machines running single channel (2GBx1)
- 4GB in all machines running ????? channel (2GBx2) [Max usable 3GB]

[Edited on February 7, 2011 at 11:41 AM. Reason : clarification]

2/7/2011 11:12:24 AM

You are upgrading TO windows xp?

2/7/2011 11:28:32 AM

I have somewhat of an inventory/audit, but I'm not too worried about ordering more than I need because I'm pretty sure DDR2 has nearly hit rock bottom pricing. Therefore, I'm looking more of an "across the board" universal solution rather than exact "4 PC2 modules for this computer, 2GBx2 modules for that computer, etc etc."

That still may not have been clear enough.

[Edited on February 7, 2011 at 11:45 AM. Reason : .]

2/7/2011 11:43:20 AM

Quote :

"- 4GB in all machines running ????? channel (2GBx2) [Max usable 3GB]"

the combo packs seem to come out cheaper, atleast looking on new egg. I would get the 2x2GB.

Also, it varies mobo to mobo with 32bit ram usage it seems. Some use only 3gb if you have 4gb in, some use 3.5gb or some fall in between.

[Edited on February 7, 2011 at 11:48 AM. Reason : s]

2/7/2011 11:48:01 AM

Price isn't the main concern. Long term value is (if that makes any sense). The 3 dollars saved on kits is irrelevant. However, 2GB modules are cheaper than 1GB x 2 right now so that may have merit. It looks like I'll need a mixture anyway, some of my motherboards only support 1GB per channel which sucks.

This is going to sound completely ignorant, but you do still get full dual channel benefits even when the OS restricts usage to3/3.5GB correct? What about when it's a chipset/BIOS restriction such as some shitty MSI boards?

[Edited on February 7, 2011 at 11:57 AM. Reason : ]

2/7/2011 11:57:07 AM

not sure. From what the nerds in CSC hardware classes have said was that using the same size/manufacturer across the slots was best.

So if you have 4 slots, 4 x 1 GB dimm is more advantageous than say 2x2gb and only using 2 slots if the board has 4 slots.

2/7/2011 12:01:41 PM

Any time I'm doing RAM stuff I normally replace with RAM from the same manufacturer (new kit) or at the least try to match the CAS timings. Matching them, however, might get you 3-5% performance increase. It's more an effort to squeeze the last drop out. Just plan adding more RAM often gets you more "speed".

Also, most machines will address around 3.5 GB of 4GB of RAM. WinXP32 can address 4GB of space - but that space includes all physical addresses - RAM, cache, CD drive, mouse, everything that has a driver with an attached component.

If it was me and you've got the budget I'd take some inventory of what machines had in them (if possible). Order 2x2GB pairs for the 2DIMM machines, and use whatever you're taking out of those to populate the 4DIMM machines (4x1GB, most likely). If money is no object I'd order a ton of 2x2GB's and sell the rest on ebay.

2/7/2011 12:29:24 PM

^That's what I was going to do. Most of the modules are 256 or 512 though so it will be tough to recycle. Money is not an object other than wanting to get the most value out of this situation. In 3 years I want to do something with the DDR and I'm trying to decide if having a bunch of 2GB chips will benefit me more than 1GBs. I don't know that I can really justify dropping 2x2GB in every machine and that's where the question of 1GB x 2 dual channel vs 2GB x 1 (with upgrade capability) came into play.

tl;dr version

Computers currently have combinations of 2x256MB or 2x512MB and need 2GB.
Do I purchase 2GB modules and lose dual channel performance but leave room for expansion and slightly futureproof or do I just use 1GB modules across the board and realize in 3 years there won't be any more of a demand for DDR2 1GB vs DDR2 2GB.

[Edited on February 7, 2011 at 1:04 PM. Reason : .]

2/7/2011 12:59:42 PM

Quote :

"So if you have 4 slots, 4 x 1 GB dimm is more advantageous than say 2x2gb and only using 2 slots if the board has 4 slots."

i don't understand why that would be the case...seems to me that more memory being accessed on a chip that's already being accessed would be faster (albeit unnoticeably) than the latency introduced by accessing a second physical stick

i'm not an engineer, though, so...

2/7/2011 1:12:30 PM

^ could be. I'm just going by what i've heard. BUT it also seems the board may clock it down if you've filled all the slots.

http://www.tomshardware.com/forum/55024-30-memory-please-read-posting

Quote :

"DUAL CHANNEL Q: What is Dual channel? A: See key term: dual-channel. Q: I currently have two sticks of 512mb pc3200 memory in DIMM 1 and 3 to reach the performance of dual channel DDR. Can I also add two sticks of 256mb PC3200 in dimm's 2 and 4 to reach 1.5GB of ram and still maintain dual channel performance? A: As long as you have matched memory pairs on each channel, you should be able to run dual channel. The only potential problem: Because you are using 4 memory modules, which require more power, your system may clock the speed of the modules down to maintain stability. Q: How do I know if dual-channel is working in my system? A: An easy way to tell is to use CPU-Z (from http://www.cpuid.com). You can check if dual-channel is enabled by looking at the memory tab. In the General section, you will see a field labeled as 'channels #' which will indicate if dual-channel is working. Q: Can I add 256MB and 512MB modules together? A: Yes. Make sure you do not exceed the total memory size. Q: Do I have to install memory in pairs? A: It depends on your motherboard. Consult with your motherboard's manual to see how dual-channel works on your board. For most dual-channel boards the memory modules must be identically sized, and have the same number and type of chips. Typically, the motherboard requires the modules to be inserted in pairs on either slot0 and slot1, or slot2 and slot3. For some other motherboards three modules can run in dual-channel (the numbers of chips, not the modules themselves, are divided between the two channels). In any case, it is best to match the latency and speed of the modules, though it is not required. "

2/7/2011 1:50:31 PM

http://www.tomshardware.com/reviews/PARALLEL-PROCESSING,1705-11.html

Great article Covers RAM, processors, and HDD when running things parallel

2/7/2011 2:07:58 PM