AMD Ryzen 9 5900X On Windows 10 vs. Ubuntu Linux Performance: Windows Looks Surprisingly Good This Time
It's looking like the core complex layout for Zen 3 where all of the cores on a die share an L3 cache may be helping with Windows 10 as compared to Zen 2 and prior these numbers are generally more competitive now between Windows and Linux. There's also the possibility of targeted improvements in this latest Windows 10 update. In any case I'll be following up with more benchmarks on more CPUs to see.
For heavy rendering workloads like V-RAY, IndigoBench, and Blender, Ubuntu Linux continued to be the superior choice with the Ryzen 9 5900X.
The Appleseed renderer on the CPU was one of the rendering exceptions where the Windows 10 and Ubuntu 20.04/20.10 performance was very similar.