I'm ordering an MSI K8N Neo4 Platinum/SLI motherboard.
I want to install 2GB of memory with the highest performance possible.
From the research I've done, low CAS and high memory speed will produce the best possible performance. (The CPU will be an AMD 64 3800+ Rev E.)

What I've been trying to figure out is how to get the highest performance within the limitations of the board.

It seems like if I can find 4 single sided 512K modules this will provide the lowest CAS (usually around 2 per module) and will allow the board to run at the max 400MHZ speed. However, if I get 2 1GB modules the CAS per module jumps up to 3 but will still allow the board to run at the max 400MHZ speed. And if I get 4 double sided 512K with low CAS then my system bus drops to 333MHZ. So it seems I really need to make sure the modules are single-sided and not double-sided, unless this is something you can set in the bios?

I'm really confused about the single-sided and double-sided limitations of the board and whether single-sided modules are even available for DDR400 memory.

I've been looking at different memory manufacturer sites and I can't figure out if the modules are double-sided or single-sided. I found an overview of some Kingston DDR2 memory at http://corsairmemory.com/corsair/pr/PR_xms2_5400ul.pdf which states it can come in a single dual module or two single-sided ones, but then on the website there is no information as to whether a module is single-sided or dual-sided. The Kingston memory is out of volatage spec for the board anyways - requires 2.5v or less and the Kingston is around 2.6v, so I'd probably want to go with another company like Corsair, but again no details as to the single- or double-sided nature of the modules. (Maybe I'm just looking in the wrong places on their sites?- I just can't find it.)

Summary:
1. Am I on the right track for a high performance memory module configuration? (4 single-sided 512K low CAS DDR400- and the board will operate at 400MHZ)

2. How do I determine if the memory I want to order is single-sided or double sided? (Or, does it matter- can it be set in the bios and still achieve the 400MHZ support from the motherboard?)

Any help would be great!

<P ID="edit"><FONT SIZE=-1><EM>Edited by Whist34 on 04/23/05 07:24 AM.</EM></FONT></P>

- Corsair single-sided modules denoted by 'A' in model number (e.g. CMX256A-3200).

- I believe OCZ and PDP have 2-3-2 (CAS-tRCD-tRP) 2GB (2x1GB) memory module kits. Would fulfill your CAS=2 DDR400 requirement.

Ok, I searched Corsair's site for CMX512A-3200 and could not find it anywhere. Does the 512K version have a different name?

I could not figure out whether OCZ had single-sided or double-sided - any way to tell?

I found this at PDP:
PEP5123200+XBL 512MB 64x64 mod. 400MHz (PC3200) 32x8 2-2-2-5-T1

I think the 32x8 means its single-sided, but I'm not sure.
Even if the PDP one is what I'm looking for it still has a 2.6v requirement when the board is only rated for 2.5v (unless I'm confused about what the board can support).

I also found this 2GB kit (also 2.6v)
PDC2G3200LLK 2GB OR 2048 MB 2 - 128 x 64 mod. 400MHz (PC3200) 64x8 2-3-2-5-T1

I don't think it is single-sided, but the low latency is what I wanted to begin with- still not as good as the 512, but does have the CAS 2

And, again, is this configuration the best:
4 512 single-sided DDR400 with low latency
(Can this be done with 2 PEP5123200+XBL kits?)
If this configuration is not the best, can you suggest a better configuration for the board?

Thanks for the feedback- got me to look at PDP, eventhough still not sure if its what I need.

- Virtually all 512MB memory modules that would be bought for this system would be double-sided. For your requirements, you're going to be using double-sided memory modules.

- Can go into the motherboard's BIOS and change memory voltage if necessary.

- I don't think i can guarantee that four double-sided memory modules will work at DDR400 + 2-2-2 timings + 1T command rate. Probably been done before though.

- In summation, would suggest two 1GB 2-3-2 memory modules like the OCZ and PDP models i mentioned above.

Great choice!

Thanks for all your feedback Prof133!
I really wish I could have found the 4 512 with 2-2-2-5 I wanted, but I can live with 2-3-2-5

I went back and looked some more at the OCZ site. I found:
OCZ EL DDR PC-3200 OCZ4002048ELDCTE-K CL 2-3-2-5
(Titanium)

Which brand is better PNP or OCZ?
I already found the PNP kit for sale at Monarch computer, but I can't find this OCZ Titanium kit yet. (I'm ordering the parts in May so no rush yet. I can wait for the OCZ Titanium if OCZ is a better choice.)

- Can find the OCZ platinum 2GB PC3200 kit at newegg with 2-3-2 latencies.

- Performance-wise the OCZ and PDP would be virtually identical. OCZ is a more familiar name especially amongst overclockers. PDP is kinda new to enthusiests but made a big splash by offering great value/dollar particularly with their XBL models. Would be happy to recommend either one.

I found it!

OCZ4001024ELDCPER2 2x1GB Kit
PC-3200 / 400MHz / Platinum / Revision 2 / Dual Channel
CL 2-2-2-5
2.75 Volts

The only trouble is the 2.75v. Any ideas on what this will do to my MSI board that will have a 2.5v rating? Should I look for another board? I was thinking of the ASUS SLI board but read reviews that said it had a cheap fan cooler for the chipset and the fan blew with extreme rpms. (I also like the fact that the MSI board has a sounblaster chip installed on the board.)

- Looked up the model number and i believe that would be a 1GB (512MBx2) kit. Here's the <A HREF="http://www2.newegg.com/Product/Product.asp?Item=N82E16820227210" target="_new">2GB kit</A>.

- Could try <A HREF="http://forums.silentpcreview.com/viewtopic.php?t=19902&highlight=a8nsli" target="_new">replacing the chipset cooling</A>.

I'm fairly certain the MSI board will have voltage adjustment. In fact, any board would have to be adjusted, they all default to 2.5v or 2.6v.

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i would go with a high performance 2x512 kit with cas 2-2-2-5 1t at pc3200. It would be guaranteed to work at these timings. 4 modules aren't guaranteed to work at their rated specs. For example i have 4x256mb of corsair xms pc3200 and i can only run them at ddr400 if i enable the 2t command.

1GB performs better than 2GB, except in a rare few cases.

I've read on Intel's site that DS (double-sided) modules perform better than SS (single-sided) modules as a general rule.

In that respect, ideally you'd want 2pcs 512MB DS.

note:
512MB SS DDR modules are built using 8 chips of (64x8), as opposed to 16 chips (32Mx8) for SS.

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