Closing Remarks
Intel anticipated a performance hit in the range of a 2 to 8% when addressing the Variant 4 vulnerability by disabling Speculative Store Bypass, but in our tests it looks more like 1 to 3%. The impact for Linux users appears to align closer to Intel’s claim and we believe this comes down to the Windows scheduler which is less efficient than Linux's.
When
patching Variant 1, 2 and 3 we had found reduced gaming performance on the i7-8700K by up to 5%, though for the most part we saw a 0 to 3% decrease in frame rates. Variant 4 has seen a further 1 to 3% dip, though this time we were testing with the non-K 8700, but the margins should be much the same across the entire range.
In other words, since December the gaming performance of Intel Coffee Lake CPUs is down by 1 to 6%, or about 1-2 fps in games pushing over 60 fps and up to 5 fps for high refresh rate gaming. Definitely not a huge deal overall, but it’s worth keeping in mind that Intel will suffer an IPC hit because of this with future architectures that address these vulnerabilities at the hardware level.
Those of you fortunate enough to own an 8th generation Intel Core processor don't need to worry about your games turning into a slideshow as the performance impact is not significant. But even if it was, we would have strongly recommended you update your BIOS and enable the mitigations as soon as possible.