Curious how much Vegas has changed in rendering Hevc and ProRes camera clips since v17 and one word sums it up... allot. Did this quick test on a medium performance Intel Nuc that I use for my Vegas work on the road. See my signature for specs. Here's what I got rendering a 30-second region with a camera LUT of similar 4k clips shot with 10-bit 420 hevc and ProRes422 rendered 1080p with Magix Avc Amd-Vce:
ProRes 422 v17.452: 1:45 sec; v18.482: 0:36 sec Hevc 420 v17.452: 0:36 sec; v18.482: 0:29 sec
Both got better but wow on the ProRes performance boost. But for the 10x clip size penalty, ProRes seems to be a practical format. Btw, on this system with v18 I could play the ProRes clip at Draft-Quarter with full and steady frame rate. Comparing favorably to Preview-Auto for the Hevc clip. With v17, could not do that on this system even at Draft-Auto.