If looking at the geometric mean of all the benchmarks carried out, the EPYC 7601 averages out to about a 1% hit with its Spectre mitigations. The dual Xeon Platinum 8280 Cascadelake setup with its mostly hardware-based mitigations was slower by 4% with the relevant mitigations enabled.
Meanwhile the dual Xeon Gold 6138 server that unfortunately doesn't have the hardware mitigations saw a 11% hit from the benchmarks run with these Spectre/Meltdown/L1TF/MDS mitigations or 15% if disabling Hyper Threading as an additional measure based on the benchmarks carried out today.
Enligt den rapporten: 4% eller 11-15% beroende på vilken processor.