Internal tests from a leading industry vendor have shown that fixes applied to servers running Linux or Windows Server aren’t as detrimental as initially thought, with many use cases seeing no impact at all.
The Meltdown and Spectre vulnerabilities, first documented in January, seemed like a nightmare for virtualized systems, but that is overblown. There are a lot of qualifiers, starting with what you are doing and what generation processor you are using.
The tests were done on servers running Xeons of the Haswell-EP (released in 2014), Broadwell-EP (released in 2016), and Skylake-EP (released in 2017). Haswell and Broadwell were the same microarchitecture, with minor tweaks. The big change there was Broadwell was a die shrink. Skylake, though, was a whole new architecture, and as it turns out, that made the difference.
Source: NW Security 1