Didn't Ryzen close the single thread performance gap quite a bit?
But yeah, protecting against it means implementing memory protection in more places in the CPU. More gates and the possibility of becoming a bottleneck.
Re:Meltdown Proof-of-Concept
by arcticbull on Wednesday January 10, 2018 @04:15AM
(#16113530)
With Ryzen, they're pretty much equal on an IPC basis.
Perhaps that because they haven't taken the speed short-cuts that Intel took...?