I downloaded the cumulative September 2024 update yesterday. I had taken a drive image prior to doing so since I do not trust Microsoft updates these days and at least being able to go back to an older build buys me time. This update was supposedly the one that "improves" Ryzen performance - mainly 4th and 5th generation but also 3rd generation like my 5800x3D.

There have been numerous benchmarks run on the previous Ryzen KB update from August that formed part of this September cumulative update and whilst most 3D apps ran no worse or even better, some distinctly ran worse. Unfortunately I am in the "worse" camp with P3D performance being noticeably more stutter-filled that it was before and this is also the case for other 3D apps that worked perfectly fine beforehand. Although some stutter in P3D and any flight sim is inevitable, it was negligible with the earlier OS build on my system and only occurred at normal "expected" times such as entering complex ORBX scenery areas for the first time.

I can only surmise that with this update, the Ryzen "prediction code" either runs more pro-actively than it did before or perhaps even runs for the first time ever (as in not working at all beforehand). It would make sense - at least to me - that the prediction code itself must add some overhead. And when the code correctly "predicts" something then the benefit of that prediction clearly far outweighs the penalty of that overhead. But when it "misses", that is just wasted overhead. That would explain why overall benchmarks taken over a period of time show better results but it would also explain why I have new stutters that I did not have before. That is my theory anyway. The results with MSFS by the way weren't that flash either.

In any event, I went back to my old image from two days ago rather than attempt an update removal. My system is back to its usual happy self. Thankfully being a simulation only machine, it won't make much difference if I just take on the security updates from this point. This is what I hate about Windows 11. It never stands still and you always hear stories about feature updates breaking things or making things worse for some people.

Thanks, yes the so called Rhyzen update is controversial. In windows settings, you can always remove an update. Or Shift Restart to reboot into the diagnostic screen instead of into windows, and then remove the last update there.