I've had a 5900X+X570 machine since late 2020, with fTPM enabled, and never noticed any stuttering. It's a completely flawless system, especially compared to the Intel 4790K machine it replaced, which had loads of random issues like these, unexplainable performance dips and crashes which no tweak could ever fix.
It really seems to vary based on motherboard make and model.
My high-end x570 board from ASUS initially exhibited this behavior, but it was rectified rather quickly with a BIOS update.
I still ended up putting in a real TPM module for convenience reasons. It's hard to experiment with bios settings when half of them end up wiping the fTPM, necessitating me to punch in my BitLocker key on next boot.
Maybe this fiasco combined with Windows 11 will finally push motherboard manufacturers to just build a real TPM into their products rather than relying on these janky fTPM/PTT solutions.
