Regarding SLI: I am afraid of it. Many game magazine reviews showed that it works only with special software. In most cases games use only one kernel of the card and so you get not advantage over a non-SLI single gpu solution. But it drains more power.
Right... but those are the same magazines that even to this day are incredibly pessimistic about the Dual Core and Quad Core performance increase of the latest processors...
I really wouldn't put too much faith in what those magazines. There are practically always performance boosts... whether it's worth the money or not depends a lot on your budget also.
Just look at the PS3, the Xbox360 .. both already have multi-core processors in them for a good reason. All the multi-platform games will take advantage of multi-core PCs because they are designed around multi-core systems.
I'm thinking the next generation of consoles will also have dual or multi-core graphics cards.
And if your game supports SLI then you get some micro-delays during rendering because of the synchronization of both cards.
Don't worry about that.
You really won't notice this... it's a lot less than a split of a millisecond and it won't ruin the performance increase at all. The relevance of these delays is really near zero when it comes to the performance in practice.
You won't get twice the performance with two 3D cards in SLi, but you will get a considerable boost. Some think it's worth it, some think it's expensive,
Cheers
