Intel Core i9 9900K Spectre Mitigation Benchmarks

With CompileBench when disabling the relevant mitigations, the kernel performance improved by 3~6%.

With Node.js, disabling mitigations improved the server-side JavaScript performance by up to 3%.

The Hackbench Linux kernel scheduler benchmark also shows overhead still from these mitigations while at least KPTI and L1TF mitigations are no longer needed/applied with the new Core i9 CPU.

The PostgreSQL performance cost is down to about 3% or less as well, much better than before with KPTI for Meltdown mitigation causing a more significant performance hit generally in these I/O heavy workloads.

With Redis the performance cost was still up to 10%.