DUAL 512MB or SINGLE 768MB

Hello readers, im currently lookin into buying a new computer at the moment the dell xps 720 appears to be the best choice for me, however im currently undecided which product in this range i should get.

The grafix card is the main source of confusion, im not really sure which of the two choices would work out better in the long run, im pritty unknowledgeable on this subject, as you can probably tell, so any information about the best choice would be great
These are the possible choices~
DUAL 512MB NVIDIA GeForce 8800GT card
SINGLE 768MB nVidia® GeForce® 8800 GTX graphics card

Thanks for any info

well 1 8800GT performs very close to the 8800GTX so i'm pretty sure that 2 GT's would perform very well compared to the GTX, that is of course if the game supports SLi.
hope this helps

here's a list of all the games currently supported by SLi:
Supported Games

I'd say get the single card; scaling is a long way from linear with SLI, even assuming that you get decent drivers. One heavy duty card will work in all circumstances, two lighter weight cards is a less certain proposition.

Another vote for 1 GTX.

two gts if the price is about the same

I wouldn't put too much emphasis between "512MB" or "768MB". The 8800 GTS Rev 2 'only' has 512MB, yet I've not seen any indication that it is limited by it even in the most demanding games/settings (something that brings the GTS to its knee, e.g. Crysis at 2560x1600, will also bring the GTX to its knee). In other word, it is at least as good as the GTX in existing games, but cheaper.

SLI doesn't scale linearly, but in games that supports it, it offers enough of a boost to easily overtake the GTX, GTS and the X2 (in a large majority of case) (see the full review). There are exceptions though. Read through this review and you'll see that the X2 is decisively faster in Call of Juarez and the the GT SLI lags behind the GTX/GTS in TF2. No one setup wins it all (discounting triple SLi or CF X2).

That said, the second review I linked is a little odd: the performane in Bioshock of the SLI setup is so different from the ones in Anandtech I have to wonder if there is not something a bit odd there (for some reason Anandtech's setup scale so much better).