AMD Zen 5 Not Affected By Inception/SRSO, mitigations=off Yields No Benefit On Ryzen 9000 Series

One of the security changes with AMD Zen 5 processors that I haven't seen AMD publicly mention at least not prominently is that the new cores are not vulnerable to Speculative Return Stack Overflow (SRSO). Unlike Zen 4 and prior, under Linux I noticed that Zen 5 is no longer affected by the SRSO "INCEPTION" vulnerability. But of course there does remain other CPU security mitigations in place carried over from Zen 4. For those wondering about the mitigation costs or if it's worthwhile running Zen 5 with the "mitigations=off" insane mode, here are some benchmarks.