TCMagazie has posted a comparison review between the Dual 6600GT vs Dual 6800
With excellent price-performance ratios and groundbreaking hardware, these sweet cards do their users proud, delivering precedently unparalleled power with their impressive feature sets, and more than doubling the results achieved by the previous generation's best performers.Read more
That's not the end of it, though. After the series' launch, in a move that endeared it to many enthusiasts and hardware nuts, nVidia then proceeded to reveal that the cards could be linked together to form a small parallel GPU processing unit, to boost power beyond the limits of any single card. Yes, gentlemen, you can let go of your Voodoo 2 cards, now. SLI is back, nVidia style.