With Quick Sync on the the Intel Pentium G4900 (8th gen, Coffee Lake-S) processor I'm able to handle up to 5 hardware transcodes from HVEC 4K HDR content without any stuttering. :
Intel Pentium Gold G5400 SR3X9 Coffee Lake 3.7 GHz LGA 1151 UHD Graphics 610 CPU | eBay
Intel Pentium Gold G6400 Review | PCMag
Intel Pentium Gold G5400 SR3X9 Coffee Lake 3.7 GHz LGA 1151 UHD Graphics 610 CPU - Dibujos-Faciles.Com