[INFO] Software HEVC encoding; more cores = what gain?

[Mozgovlom]

For HD and higher resolutions x265 should scale relatively linear. So doubling the core count while keeping the frequency would double the fps.
Vapoursynth can vary a lot.
If you post more details about your workflow I can run it with my Ryzen R9 3950x and report back.

Cu Selur

Since those old Xeons are really cheap and after some more thinking I went and ordered a mobo+cpu kit. So your answer is very reassuring, thank you.
I can't even think about troubling you with any test runs, but I will try to post my own comparison results for future reference when I'll set everything up.