AWS patched their hosts back in 2018 which caused a huge shitstorm in terms of performance lost across various workloads..so yes.

https://blog.appoptics.com/visualizing-meltdown-aws/

Afaik amd patches aren’t as penalizing as Intel ones. I have no idea if ^^^ refers to bare metal, bare metal w/ patches or cloud env (unlikely) hence the question.

The link above is specific to AWS -- hence, "Visualizing Meltdown on AWS" as their title.

Don't know, but for pure numeric code these mitigations are not (AFAIK) that expensive. The main cost is incurred for any code that is syscall-heavy like I/O.

Pure numeric benches aren’t very useful irl tho. My hunch is with security patches single core will be very comparable

These are VMs, the hosts have to run with these mitigations enabled.