I am looking at building this board;

MB == Gigabyte GA-7NNXP
CPU == AMD XP 3000+
Case == Antec or equiv. w/ 400W PS
HD == (2) 80GB Seagate SATA/150
CDRW == Yamaha CRW-F1
Video == PNY Quadro 750XGL
OS == Windows XP

But now I am stumped on the RAM. I would like to have 1.5-2.0GB of DDR400 RAM, but the only way I can get that is to buy 2 1GB modules? This board has four memory slots, but to get dual channel with four memory modules you need DS or SS memory. The manual specifies this;

DIMM 1 == DS/SS
DIMM 2 == DS/SS
DIMM 3 == SS
DIMM 4 == SS

When purchasing memory off the web, how do I know if it is DS or SS?

Do you have to have an equal number of memory modules to use dual channel? For instance, can I use 3 X 512mb for a total of 1.5GB and still be in dual channel?

Sorry for the length, but thanks.

I fear there are only two ways to know if it's Double or Single Sided.
You can ask or you try to find an image or description on the site of the manufacturer. But to do the last you need the exact name of the ram modules!

With three ram sticks you can definately not use the dual channel and I'm not sure if it works with 4 sticks.
the idea of dual channel is the the data stream is written to two ram mudules at the same time to speed it up.
If it works with 4 stick you have to check the manual or maybe someone else knows!

I think you better read this:

"Buyers enticed by dual channel DRAM should note one crucial thing: in theory, a dual-channel memory link does not bring any benefits since the data rate is limited by the FSB bus's bandwidth. It's fixed at a maximum 200 MHz (Athlon XP 3200+) to give a bandwidth of 3.2 GB/s. Even using fast dual DDR400 memory with an access time of 6.4 GB/s has no effect on the Front Side Bus bottleneck of 3.2 GB/s. With that in mind, it's really not so inappropriate to question dual-channel memory technology on the Socket A platform."

http://www.tomshardware.com/motherboard/20030908/index.html

That makes more sense now.

So the best I can do is 3 X 512mb? Or does anyone make 1GB sticks? All I can find in PC3200 is 256 and 512...

I don't know if you checked the link & read the article, but I was surprised to read that AMD has discontinued the Socket A platform...

Anyhow, what are you planning on using this system for? Unless you're gonna use it for CAD, video editing or some other memory intensive programs, there's really no need to install more than 512mb of RAM...increases from 128 -> 256 -> 512 have a significant impact on performance, but going beyond 512mb does very little more...UNLESS you have programs that can make use of it. Based on your videocard choice though, I'm wondering if possibly you're building a CAD/workstation rather than a gaming machine?

Yes I did read the arcticle. I actually have read it before, but skipped over parts.

The machine will be used for CAD(SolidWorks) where at least 1GB is mandatory.

Thanks for your help.

Pricewatch.com has them listed