Video card question

I have Doom 3 (purchased copy), my question is about texture memory. To play this game in ultra game mode, it said i need 500 megabytes of texture memory. What is that and how do i know what i have ?

My computer specs
AMD Athlon 64 2.40 Ghz
512KB L2 Cache
1600 Mhz FSB
320 GB HD
ATI Radeon X800 XL PCI Express
256 MB GDDR3

Any help would be appreciated

Sounds like they are saying that you need a dual SLI (2 x 256mb video cards) to get the most out of it. I wouldn’t worry about it. I’ve played doom3 on my geforce 6800 (non gt) at pretty high settings, and it looked great and played fine. I sure didn’t see any need to max it out to the ultra settings.

Yep, they’re saying that to play with the highest settings you need a card with 512MB of RAM… or 2 cards with 256MB each (a lot easier to pull off). But honestly, the game runs great, even on much older hardware (my Radeon 9600 ran it ok, for example) than your X800XL, which is the second fastest setup you can have nowadays after nVidia SLI.

I thought PCI-E could do textures across the bus, much faster than with the old “AGP aperture” method, as PCI-E 16x is much faster.

Thanks for your replies and help