512mb Over 256mb GDDR3 - Whats The Benifits?

I have just been surfing my fav websites for that special deal on hardware for my 939 build (I don't se the point in AM2 cos I got my 939 board free). Anyways I have decided to purchase the following on what I think will be just great for me.

ECS Nforce4 A939 Board (I got it FREE whooop)
AMD 64 939 3700+ San Diego
GEIL 2GB PC3200 DDR Kit
WD Raptor 36GB HDD
WD 250GB Cav SATA HDD
Lite-On SATA DVD-RW Drive (Black)
Samsung SATA DVD-ROM Drive (Black)

Now for the PCI-E card I was thinking of purchasing either the BFG 7900GS 256mb which is £130+ del. Or the Gainwood 7900GS 'Golden Sample' 256mb for £127 at overclockers.co.uk but they have a OC labled card with 512mb GDDR3 for the same price as the BFG. Is there any benifits of having 512mb memory when playing games and stuff I suppose loading graphics would be a lot faster ect but I just would like to know more on this question.

Very nice setup ,

Not many games actually use 512MB, unless you running it at a real high res e.g. 1900 x 1200. I recently aquired the 8800GTS 640MB from EVGA and it does the business on my 19" widescreen . much better than my old 6 series card. Over at ebuyer they've got the 320MB model for £185 with free shipping.

you'll see benefits with 512 as soon as 1680x1050 or 1600x1200 on alot of games these days.

But the card matter also

What resolution monitor you using? <----- What matters

AA, AF seem to eat up the vram pretty quick. Additionally, framerates alone may not tell the whole story. This article does a head to head comparison. Particularly interesting are some of his analysis of drops in framerate (stuttering) when he didn't have enough vram that didn't really show up in the averages in some of the framerates. Some of his benchmarks could definately be a bit more exact, but its an interesting article and I haven't seen one that tries that approach between them.

Vram, in theory should be just like system ram...if you don't have enough for the task, things suck! But if you have enough for the task, adding more doesn't really make a signifigant difference.

The 320mb versus 640mb 8800gts are kind of interesting because I think there is a bug in the drivers thats making the 320mb take a much bigger performance hit then it should at settings that use more ram then it has. Nothing else really explains why its outperformed by a 256mb x1900xt (with less ram) in some of Anandtechs benchmarks for instance