These few vulnerabilities claims to be the most widely spread potential security issue in the last few years. M$ and Linux has provided corresponding patch in fixing it. However, the fix is not free, it usually counts for ~10% of performance reduction, the effect may be magnified in IO intensive usage.

I found my machine compiling our source slower than before by slim margin (~30 sec difference) and try to dig out the reason of the slowness.

There are ways to stop the patch in either Linux and Windows.

Linux
http://wayoflinux.com/blog/meltdown-spectre-performance

Windows
https://www.grc.com/inspectre.htm

Honestly, I am not a terrorist nor government officers, given my notebook is sitting behind the company firewall, I am safe to reclaim my PC performance. You may check that out too, but do at your own risk.