[qwerty456127]

I see. Quite a reasonable, detailed explanation, thank you. I didn't notice any visible difference in perceived performance (just using the PC to write code, browse the web and watch videos) when I switched spectre/meltdown mitigations on/off on my old Core 2 Duo PC though. It just always worked perfectly fast.

Meanwhile, I often don't need any network connection (when coding, watching pre-download videos, or running data/number-crunching or build scripts). Can I expect 90s-like efficiency if I disable all the mitigations and hardening stuff?

[Seirdy]

There are...a lot of good reasons to keep the mitigations enabled. All nontrivial software has bugs, and hardening measures can keep some of the worst ones in check. Frankly, the Linux desktop needs more of this, not less.

That being said, one writeup explained how disabling several mitigations improved http server perf by several factors: https://talawah.io/blog/extreme-http-performance-tuning-one-...