Re:AMD Disables Zen 4's Loop Buffer
by baq on Sunday December 01, 2024 @11:28AM
(#42289176)
Indeed, it might be the case that there’s more than that disabled, since numbers are somewhat surprising:
> Still, the Cyberpunk 2077 data bothers me. Performance counters also indicate higher average IPC with the loop buffer enabled when the game is running on the VCache die. Specifically, it averages 1.25 IPC with the loop buffer on, and 1.07 IPC with the loop buffer disabled. And, there is a tiny performance dip on the new BIOS.
Smells of microcode mitigations if you ask me, but naturally let’s wait for the CVE.
> Still, the Cyberpunk 2077 data bothers me. Performance counters also indicate higher average IPC with the loop buffer enabled when the game is running on the VCache die. Specifically, it averages 1.25 IPC with the loop buffer on, and 1.07 IPC with the loop buffer disabled. And, there is a tiny performance dip on the new BIOS.
Smells of microcode mitigations if you ask me, but naturally let’s wait for the CVE.