I bet nobody expected this! A chart is worth a blizzard of numbers:
The project is the old Red Car benchmark that's been around since vp10 with the original media transcoded to 4k Hevc. Times are for HD & 4k renders, both with the default Magix Qsv preset. Nvidia and MainConcept, and even Voukoder renders all show similar speed improvements. Regular qsv decoding has always been faster than high-quality legacy-hevc. And experimental hevc still is, but look how the performance gap has been closed! And without the loss in quality that accompanies pure hardware decoding. Can't wait to see the performance numbers from my higher powered desktop that's still crunching away upstairs.