Wasn't the bios also involved in these mitigations?
In so much as a micro-code patches for the processors are concerned - yes. My processor is updated to the most current, Oct 2019. Doesn't matter - performance still sucks!
I applied these reg changes, rebooted - then applied a script I've done many times before. It was amazing how slow the script ran compared to other machines. I took a video, I'll see about posting it later.