Radeon X800XL 512MB Review
 

ATI has introduced the Radeon X800XL with 512MB of local video card memory. Inside we examine this video card and see if the extra memory will actually improve your gaming experience.

http://www.hardocp.com/article.html?art=Nzgw

videocards don't need more memory to run faster, 256Mb is more then enough, even 128Mb with games at 1024x768 (still most used resolutions) is enough:)