Differences in Card Memory

[Firix]

Okay, so I'm currently running the following:

Celeron 2.4ghz.
512MB DDR 400 (2x256DDR)
NVidia -- TNT2 32MB

I know, the GFX is sh*t.

Now, my question. I have been looking at GFX cards on various sites,
and I was wondering this; If my computer runs DDR memory, and
I install a GFX card with 512MB DDR2 or 256 DDR2 or something alike,
with DDR2 memory, will it work?

Also, if not. Can anyone direct me anywhere that has DDR GFX cards?

 

[The_Other_One]

GPU's and system RAM are totally separate. What you need to find out is if your board supports PCI or AGP graphics.