Okay Sammorris; how useful do you think SLI is for someone on a limited budget? I am pondering it more for the question of future compatibility than anything else. Just imagining using multiple video cards, rather than shelling out HUGE $$$$$ for a top of the line one...
I think it's the least worthwhile thing a budget user could possibly do, save suspending the computer from a tall building. In a large number of games, performance gain is minimal or even negative, so IMHO it's a waste of money that becomes more and more of waste depending on how expensive the GPUs that you use are. If you had two 6800GS 512MB cards for about £300 total, you can put a 7900GT in for £50 less and absolutely Annihilate them.
