Efficient multithreading is a pretty significant challenge, especially as core counts have really ramped up over time. As I said in that thread, using "real" (physical) cores and avoiding use of HT (easiest to disable it in the BIOS, though I know this makes it unavailable for all apps, which is a disadvantage) should give decent scaling even past 32 threads. I suggest you test that (HT disabled in BIOS) to see how well it works. If it's still not taking good advantage of your system then let us know.
Regardless we continue to try to optimize the renderer over time and it should get steadily more efficient on high-thread systems in the future.
- Oshyan