Questions

I am in the middle of getting a system together.

So far, it's looking like an Asus A7V8X mobo and AXP 2200+.

So, it'll be running more than likely at a 266Mhz FSB.

I was looking at Corsair RAM, specifically CM64SD512-2100 and the CM72SD512-2100.

What is the difference between the 64x64 and the 64x72?

Both otherwise have the same specs, just this different configuration. If anyone could recommend any other sticks for this application, it would be appreciated.

I am only looking for 1 stick of 512 preferably unless someone can say otherwise to using 2 or 3 sticks (Windows XP Pro will be the OS).

x64 are unbuffered non-ECC DIMMs, x72 are unbuffered ECC DIMMs and x72-R are registered ECC.

If your system doesn't support registered DIMMs you cannot run them. If the ECC is not supported by the chipset, you can still run it but it won't work.