The Current Intel Coffee Lake Mitigation Performance Impact With Linux 5.9

But long story short, while the overall performance may have improved with FSGSBASE, those gains are much more isolated than what can be found with still the widespread impact of these mitigations on all but the very newest Intel CPUs.

Of course, the test looking purely at the context switching performance is most impacted.

The web browser performance impact remains quite visible even with the latest software advancements in recent months.