512MB of graphics memory makes a difference
 

WE HEAR that if you put a 512MB graphics card under heavy stress you will see some worthwhile performance beyond that of a 256MB card but just in the most extreme cases.
A Danish colleague managed to prove such a thing when testing Doom 3 and Far Cry on a Geforce 6800 Ultra SLI, a Geforce 6800 GT and a Sapphire x800XL Ultimate with 256MB of memory and a Sapphire x800XL with 512MB.

On Nvidia cards he used 4X FSAA and 16X Anisotropic while on ATI cards he used maximal settings: 6X FSAA and 16X Anisotropic and 1600x1200 resolution.

We were surprised to see that in Far Cry under similar circumstances, the two ATI cards were able to beat both Nvidia's 6800 Ultra and 6800GT SLI.

Even a 256MB ATI card was faster than both SLI setups, while the 512MB version blew Nvidia's brains out.

As a matter fact, Sapphire's x800XL 512MB is twice plus faster than two 6800 Ultra cards under these circumstances. Very strange and interesting finding, I have to admit.

http://www.theinquirer.net/?article=23528

not true if you believe this review: http://www.firingsquad.com/hardware/...ltra_oc_512mb/

This is a tough one to call, and it took collaboration between a couple of FS staffers to determine if spending one grand on a graphics card represents the epitome of hardcore or the depths of foolishness. In the end, we fell right about in the middle. Although it seems that adding another 256MB doesn’t do much for performance in a vast majority of situations, today’s games don’t necessarily exploit all that is available. Beyond the application side, there’s a good chance NVIDIA’s driver situation isn’t completely optimal, either. Due to instability with the official drivers from NVIDIA’s site, we were compelled to look elsewhere. Our problems were confirmed by QA and an NVIDIA representative commented to the effect that our beta drivers were indeed the best possible solution for now.