There is also this site which hosts „optimized“ builds: https://chromium.woolyss.com/download/

Problem is that some of those compiler flags (avx) break stuff in unforseen ways which is a reason why they are not used in the first place. I had some strange bugs/behaviour when using those builds.

What really makes a difference is to disable site isolation (the Spectre/Meltdown patches). From my point of view this is a mostly useless feature when using uBlock or different browser windows for „private“ stuff (eg server logins, etc). Would be interesting to see how high the performance impact is with site isolation disabled.