Just stumbled upon these forum threads
Basically, in latest beta they've added AMD/Nvidia GPU hardware decoding for h264/HEVC.
Haven't tried it yet, might wait until official release. But this is very exciting, I was actually actively searching the web (not the first time) for this and now it's finally happening. I guess it's especially rejoice for AMD and non-gpu Intel CPU users since they were missing out on QuickSync playback.
To be fair, there was already an existing third party plugin for that called Turbocut , which also had Nvidia decode/encode and even their own editing codec. I've tried it once and the playback was definitely better than QuickSync (HD Graphics 630) but there were some weird audio pops so I uninstalled it after trying out.
But having this added officially to Premiere is a big deal, along with earlier hardware encoding update, and it's great they're finally doing it this year.