If you're looking for relatively high and deterministic performance maybe Project Denver, the descendant of the Transmeta's Efficeon, would be a better choice? Of course the binary translation has tons of potential for introducing bugs but since it has an exposed pipeline the translation software would have an easier time guaranteeing you wouldn't run afoul of Specter. NVidia's incarnation seems about as fast as an A57 which isn't great but isn't peanuts either.

https://en.wikipedia.org/wiki/Transmeta