Yeah I might have overstated in on Ampere given that their floating point performance is not that great. I was thinking of their integer performance, as that matters a lot for general purpose serving. The Altra uses Neoverse N1 cores which are more for general purpose computing not HPC stuff. If you want to beat EPYC on floating point you likely want one of the Neoverse V cores. We'll see what the results for Grace Superchip will be.

Anyway my writing here isn't based on those articles linked per say. Much of it is based on earlier reading and discussions with people implementing these kinds of solutions in the cloud.

Earlier analysis when Graviton2 came out for instance showed that Amazon was able to offer more performance per dollar than the competing x86 solutions.

Other vendors I have talked to have said they get even better results with Ampere in terms of performance per dollar. When I get time I will see if I can get some more solid quotes on that.