Benchmarks Of JCC Erratum: A New Intel CPU Bug With Performance Implications On Skylake Through Cascade Lake

So while the overall impact is on the smaller side, there are more workloads we're seeing impacted by the JCC erratum microcode update compared to say the affected workloads by Spectre / Meltdown. The PHP performance was one of the more sizable cases where both systems recorded about an 8% hit following the microcode update.

When going off the tests ran on both systems, transitioning from the current to new microcode meant about a 3% lower performance based on the different test profiles used and when running with the patched assembler was just a 1% performance loss overall.