On 2/7/22 09:10, Alessio wrote: > Oh, well, it was plain "kvm64". Selecting "Nehalem", "SandyBridge" or > "Westmere", it works. If you plan to live-migrate VMs from host to host, selecting a specific CPU which is the oldest generation CPU among the possible hosts which will run the VM is a good idea. Otherwise, you should probably select the option to copy the host CPU for best performance. If you don't do that, you're unnecessarily restricting guests from using features present in the host CPU.