Does GTX 770 support 4K?
Technically, the GTX 770 can run at 4096×2160 (4k) over HDMI at a 24Hz refresh rate. Over DisplayPort, the same is upscaled to 4k at 60Hz. Besides, the maximum supported resolution in the specs sheet is 4096×2160 anyway (for VGA it’s half that).
Does the GTX 770 support UHD video?
Of course the GTX 770 can not decode HEVC/H.265 (which are often used for UHD), but H.264 UHD should work fine: Like chummy02 said: frame rates matter.
What is the best GPU for gaming on a single monitor?
Both Forbes and MaximumPC recommend the GTX780ti as a “minimum” standard for “gaming” on a single 4k display as this will allow “most” titles to run within an average of 30-40FPS with minimal Anti-aliasing (4x or lower).
Can the GTX 770 decode HEVC video files?
Of course the GTX 770 can not decode HEVC/H.265 (which are often used for UHD), but H.264 UHD should work fine: