It is a single GPU. He's thinking of the GTX 690. Which is a $1,000 dual-GPU card with two 680s (underlocked like 590? I don't know).
I have a GTX 590, which is two underclocked 580s on 1 board. Problem is VRAM constraints, though. I only have 1.5GB of VRAM available to me. I don't know if Nvidia fixed all that bullshit for their 690, but I hope so. 590 launched with an incredible amount of issues, I regret purchasing it, but I can still play games downsampled at 60fps, so it's not a total waste.
In hindsight I should have just bought two 580s and put them in SLI for a nominal extra cost, my rig is two years old now, but that was top of the line when I built it.
Yeah sorry I got confused.