SLI-7900gtx better than the new 7900GX2 when not quad just "SLI"?

http://forums.guru3d.com/showthread.php?t=182361

According to that thread, two 7900gtx are better than those quad-SLI cards if you're just using "two" (or one) instead of the 4. Is this true?

Edit: Oh, and as to clock speeds/etc.....yes, Quad SLI cards (the 7900GX2 specifically) are clocked slower than their non-quad able counterparts. . . .

Click to expand...

Is that the case w/ that 7950 or whatever GPU from Nvidia being released soon, the one w/ 1gb of VRAM?

from the first reviews i saw - the dual GPU single cards performed almost identical to 2 single GPU cards in SLI - really their is no diff.

the two gpu's have to share the same 16 channels from the pcie slot, where as two sli cards (on newer chipsets) have 16 each. i'd say thats a possible reason, but then im on agp, so i can't confirm it. Just a hunch

they arent saturating the 16x lane i dont believe though - cause less information has to be send via the PCIe lane cause both GPU's are on the same card using a high speed connectors on the card it's self.

So if anything the dual GPU' card should use less PCie bandwidth in the end cause it doesnt have to pass info to another card.

The biggest difference between a pair of cards and a card with a pair is that the latter uses slower core clocks and memory. Two 7900 GTX cards would be faster in theory. I don't have a quad SLI rig (yet, evil grin) so this is only in theory. Before to long I can share information with the world!

Anyhow, the cards that are out now, from Alienware and the other high end boxes from OEMs use 1GB of memory. It is divided up between the two cores and each card uses 8 PCI E lanes. The entire card gets a full 16X and nVidia has placed a bridge chip directing 8 of the lanes to the other card. Sicne there has yet to be a card that will effectivly use more them 8 lanes this is not a problem.