NVIDIA Quad SLI not as good as anticipated
I know that when the first iteration of Quad SLI came out, it was the hot thing. Every boutique PC manufacturer was clamoring for the ability to offer it, and the few that got it sold those things like hotcakes, these days however, things aren't going so well on the Quad SLI front.
The original Quad SLI was never made available to consumers, so eventually NVIDIA released some new dual GPU graphics cards that allowed for a sort of pseudo quad SLI. These new 9800 GX2's were supposed to be the savior of Quad SLI and according to HardOCP and PC Perspective NVIDIA seems to have missed.
That's to say the $1200 worth of graphics cards alone probably isn't worth it. I don't think they'd say the same thing about the card individually, I just reckon they expected more performance from a pair of them in SLI configuration than what they got. In fact, they tested this quad SLI config against a SLI config of a pair of 8800 GTX's and found that in their three game test (Jericho, Crysis, CoD4), only Crysis showed better performance from the quad SLI than from the dual 8800 GTX's, so, more or less, their recommendation is to get SLI set up on a pair of 8800 GTX's that together cost only marginally more than one 9800 GX2 and call it done until NVIDIA comes out with something that truly offers up the performance benefit we were all looking for.