It's not only available in 480p, youtube-dl can download higher resolution AV1 videos from those links.
MPV can do the playback, stutters a bit even if my Ryzen 1700 is under 20% load (with VMware Workstation running VMs and other softs running in the background) videos look like they are...
The question now is when will we have full fixed function hardware decoding of AV1 on GPUs and mobile SoCs?
AMD is already lagging to support fixed function HW decoding of VP9, only hybrid to this date.
Right GPU load is reported under 3DMark 2013, GPU-Z's Render Test tool, Unigine Heaven 4.0 and Valley 1.0.
I did not try with older drivers yet (I'm on latest AMD beta drivers).
http://www.evga.com/precision/ seems to target Geforces only.