An AMD Ryzen 9 7950x3D has 16 physical cores and 32 logical cores. The diminisshing return for thread counts above cores / 2 is likely due to using the logical

An AMD Ryzen 9 7950x3D has 16 physical cores and 32 logical cores. The diminisshing return for thread counts above cores / 2 is likely due to using the logical core count, not the physical core count, as SMT doesn't improve every type of performance. It's not the fault of Firefox, but an aspect of the CPU design.