[swift532]

Are you sure they are not optional? I remember disabling various security updates at the time, but unfortunately I wasn't testing whether performance in games was affected positively after removing them. I can only say that it felt as it had been faster, but I hadn't measured FPS.

[metalliqaz]

My understanding is that newer Windows version contain microcode updates for the processors, and once they are applied, they are in there for good.

[mgiampapa]

Microcode doesn't flash the CPU, it's loaded at boot time, you can remove it and disable the software mitigation.