NVIDIA has silently implemented a workaround into the 340.43 beta driver for 4K 60Hz single-stream displays to be driven over a Kepler-powered HDMI 1.4 connection. Previously, 60Hz 4K was only achievable via DisplayPort 1.2 or HDMI 2.0, the latter being a standard that has yet to really reach the consumer market.
The above image shows an example of chroma subsampling, the compression method used to trim down the bandwidth of the outbound video signal. On the right, 4:4:4 is the sampling rate of a full chroma resolution. On the left, 4:2:0 is what NVIDIA has chosen to push the massive resolution over HDMI 1.4.
While it is technically 1/4 the color range of full resolution, it’s not as cut and dry as losing 3/4 of the image quality. DVD’s, Blu-Ray, and most H.26x video is natively stored at 4:2:0 sampling. This isn’t going to be a headlining feature of Kepler cards or 4K panels, but for early adopters who’d value a faster refresh rate over color accuracy, this should be welcome news.