New to the forum. I thought I would post some benchmark findings.
After much tweaking I managed to get 2:15min result.
This was with an AMD Threadripper 64 core. It was overclocked to 4.0GHz using a very extreme air cooling solution.
Gigabyte Aorus Xtreme motherboard. 7x140mm fans, Noctua air cooler.
Memory was running at 3400MHz. I had to turned of SMT to make Terragen use all the cores properly.
The fastest result I got without using overclocking was 2:45min. However the results are a bit random, sometimes it is as slow as 3min:10s and sometimes lower.
It is also worth pointing out that this results favores CPUs with less cores that run at higher frequency. The reason is that the last minute often only a few cores are used. So for longer render times (I often do renders that takes hours) then the difference will be even larger. For that reason I think maybe the benchmark should be updated or even better if the render process could use more cores even for shorter renders.
I'm bulding a second machine that I hope will be permanently overclocked using 64 cores. I got 3 radiators 2x480mm 1x140mm radiators and 15x140 fans. My hope is that I will be able to run the CPU stable at about 3.7GHz. With my current setup it will drop to 2.8GHz under full load.
Happy to answer any questions if there is interest.