Performance impact of Spectre, Meltdown patches on Windows

From Microsoft's blog:Last week the technology industry and many of our customers learned of new vulnerabilities in the hardware chips that power phones, PCs and servers. We (and others in the industry) had learned of this vulnerability under nondisclosure agreement several months ago and immediately began developing engineering mitigations and updating our cloud infrastructure. In this blog, I'll describe the discovered vulnerabilities as clearly as I can, discuss what customers can do to help keep themselves safe, and share what we've learned so far about performance impacts.The basic gist here is this: the older your processor and the older your Windows version, the bigger the performance impact will be. Windows 10 users will experience a smaller performance impact than Windows 7 and 8 users, and anyone running Haswell or older processors will experience a bigger impact than users of newer processors.