Forum Discussion
Installing Hyper-V on Windows Server 2022 reduces host system CPU to 1 core 1 thread
Got it! My colleague searched and searched for it. And found a workaround!
Ok, the workaround is nasty and shows a problem in how HyperV 2022 in somewhere in the latest Windows Updates communicates with the BIOS and CPU.In the BIOS, go to Advanced -> CPU Configuration -> Advanced Power Management Configuration -> "ENERGY_PERF_BIAS_CFG mode". Edit this option.
You will find six options;
* Extreme Performance (does not work)
* Maximum Performance (does not work)
* Performance (works)
* Balanced Performance (works)
* Balanced Power (works)
* Power (works)See following screenshot as example:
Select one of the working templates and you will get the CPU cores back.
But why?! It looks like there is something wrong with the exposure of the CPU C-states. In this particular situation is looks like it have to do something with CPU masks and with HyperV not accepting/recognizing them:
"Extended Auto-HALT State C1E"Sander.
I'd check the chipset has been installed (Intel INF)
Super Micro Computer, Inc. | Support | Resources | Results
- Yes, I've tried with both Supermicros driver and Intels official chipset driver, with the same result.
The vendor will be your best resource for problem with the hardware.
https://www.supermicro.com/en/contact
- I'm not sure I follow the logic, it works fine with Server 2019, why would a hardware problem manifest itself in that way? But yes, I have contacted the supplier. They were unaware of the problem and didn't have any suggestions beyond contacting Microsoft, as they are of the opinion that it is a software problem.
Funnily enough, they linked me to my own discussion thread on serverfault.
