I would not use that as a computer monitor but okay it appears that it uses a 1080p input and up converts it if it does process a 4K input it will be limited to 30Hz as that's the limit of HDMI1.4 and 30fps cap no thank you.
Well refresh rate that's another story, gaming would be limited to 2560x1600 @ 60Hz, so it obviously would be wiser to buy a TV with no higher res than that. Now I was about to write "unless gaming is not the main purpose.." but how else you could possibly take advantage of such enormous res? Photos - maybe... but that's pretty much it and not worth it if you are not a professional photographer... As far as know ultra hd's with display port support are in whole different price range. IMHO even if they wouldn't, it's a total waste of GPU resources... It's not like you are going to stare at it from a couple inches distance anyway...
I think this thread has got a bit lost somewhere. My gtx680`s have 2 dvi ports one is dvi-D only and the other dvi-i ,your friend will need to read the manual or box to find out which ports can be used with the correct adaptors The info AMD provides DisplayPort 1.2 Max resolution: 4096x2160 @ 60 Hz per display Multi-Stream 21.6 Gbps bandwidth (HBR2) High bit-rate audio Quad HD/4K/UHDTV display support 1080p60 Stereoscopic 3D (Frame Sequential Format) HDMI® (With 4K, 3D, x.v.Color™ and Deep Color) Max resolution: 4096x2160 @ 30 Hz 1080p30 Stereoscopic 3D (Packed Frame Format) Quad HD/4K/UHDTV video display support Dual-link DVI with HDCP Max resolution: 2560x1600 VGA Max resolution: 2048x1536 If your friend has 4 dp ports then in theory he can run 4k off any port,but i assume only one 4k device per card at any one time but regardless...the 55"(http://www.samsung.com/uk/consumer/tv-audio-video/television/led-tv/UE55F8000STXXU) will only run1080p
Actually the 7990 can run a 4k display on each display port. Hilbert did a news story on a 4k eyefinity setup a few weeks back.