I recently tested using mitigations=off in my grub boot parameters, and found that my Celeron N4000 CPU on my thin and light laptop has almost doubled in performance! I can easily see the difference... and that is with my CPU governor set to powersave.
I knew that the meltdown and spectre mitigations cost a CPU performance hit, but isn't hugely noticeable on higher horsepower chips. Before and after disabling the mitigations I ran sysbench:
sysbench cpu run --threads=2
My performance is doubled in the benchmarks!
My question and reason for this post: With Firefox 76 installed and that I'm using the latest available updates for the kernel and all other packages (I'm on Manjaro), etc... just how at risk am I of a malicious website or remote attacker exploiting the vulnerability? If the likelihood is super slim or if the attacker requires physical access to my computer, I'm comfortable with leaving it off.