Most Turing and above Nvidia cards have support for hardware accelerated decode of h.265 [0]. Modern Intel chips also support hardware accelerated decode (support started with Skylake [1]). Not sure about AMD.
Right, so that's 2 of the top 10 and 4 of the top 20 gpus per the steam hardware survey, representing 10% of steam users: https://store.steampowered.com/hwsurvey
But I don't think desktops are the problem anyway as opposed to laptops/tablets. Desktop cpus are perfectly capable of decoding h265 in real time without acceleration
Looks like most of the cards in the top 20 support H.265 4:2:0 (NVidia 10XX and up), just not 4:4:4 (NVidia 16XX and up).
I don't think the steam hardware survey is a good sample of the wider computer market though - the majority of people using youtube/netflix/etc on x86 devices are probably using Intel laptop chips with integrated graphics, not $500+ dedicated GPUs.
(Although presumably this is probably becoming less true over time, those low end users are moving more and more to mobile devices and smart TVs/chromecast/console, leaving workstation/gaming systems to be a larger percentage of the market)
Actually, Maxwell (9xx) already supports hardware-accelerated H.265 decoding, but on first-gen Maxwell (the higher-end GTX 970/980 at least) it's not pure hardware decoding and didn't work on Linux last I tried.
[0] https://developer.nvidia.com/video-encode-and-decode-gpu-sup... [1] https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video#Hardwar...