We haven't seen any graphics cards with more than two GPUs since 3Dfx's Voodoo 5 6000 (which never hit the retail market), but according to a rumor this may change with the release of a quad-GK104 graphics card!
VideoCardz read at German tech site Hardware.net that one of NVIDIA's AIB partners showed off a quad-GK104 graphics card behind closed doors during Computex.
Hartware.net claims that this quad-gpu card would require 600 to 800 Watts. As the source further reports, manufacturer is doing it’s best to keep the Wattage as low as possible. This would obviously require some limitations to the clocks, which were not yet determined.
While, this all sounds crazy and unbelievable, GPU history know such cards. Back in 2000, 3Dfx announced Voodoo 5 6000, which was also featuring four GPUs. Unfortunately, it was never released and there were at most 150 of them produced (while about 30 were actually working). You probably wonder how much would such quad-GK104 card cost? Probably around $2000, but that’s nothing compared to those 3Dfx cards now, what you can see in this video is probably worth more than some good car.