[nine_k]

Of course server CPUs can run all cores at 100% indefinitely, as long as the cooling can handle it.

With 300W to 400W TDP (Xeon Sapphire 9200) and two CPUs per typical 2U case, cooling is a real challenge, hence my mention of water cooling.

[wmf]

I disagree. Air cooling 1 KW per U is a commodity now. It's nothing special. (Whether your data center can handle it is another topic.)