gtx490?
 

Does anyone know if there ever were a gtx490? I know there was never such a card released to the public, but was there ever an experimental card that was never released? Was the 400w goliath more than a rumor? (Yes, i'll be ashamed if you guys tell me there was one that i just never heard of :/ )

Wasn't there the Asus Mars?

The Original Mars was a dual GTX285, then came the Mars II - a dual GTX580. They made was also the Ares - a dual 5870. The only 1st gen fermi dual GPU was EVGA's GTX460 2win.

The gf100 core was too power hungry for dual gpu on single pcb design. So they had to wait for the revised gf110 to be able to create the gtx 590. Even there, they had to downclock the cores to fit in a reasonable thermal limit.

For the 400 series, the closest to the gtx 490 is the gtx 460 2win, sporting two gf104 cores on a single pcb. Here's my sweet little folding beast:ph34r::

Oh, that's right, now I remember. They were going to do a Mars II with two 480s but it was taking so much time to resolve the thermal issues that by the time they were getting close the 580s were already out, so they just went straight to them.