Q: Why is macOS CPU-perfomance massively below of Windows and Linux?

[penzelan]

Hi everybody

I am observing a strange behavior on a freshly installed PVE 8.2.2 (Intel i5-7600K/4 cores, 64 GB RAM), which I have never noticed before.

Two VMs are installed: macOS Sonoma (via luchina-gabriel/OSX-PROXMOX) and Windows 11. In both cases, the processor type is set to "Host" and all 4 cores are passed through to the host.

If I run a CPU-only Geekbench immediately after installing the operating systems, I get 1000 Single Core / 2600 Multicore on macOS - and 1400 SC and 4000 MC on Windows 11. As a test, I also tried Ubuntu 24.04, where I achieved the same values in Geekbench as under Windows.

What can have such a big influence on Geekbench under macOS that the performance is so massively below that of Windows and Linux?

Any hints?

Thanks, Andreas

 

[_gabriel]

try set mitigations=off as PVE kernel options.

 

[penzelan]

Hello _gabriel

If I understand correctly, this affects all VMs on the host and would not have different effects on individual VMs.

In fact, I had already tried this - and it does indeed make a difference whether mitigations are activated or not. And these differences can also be seen in all VMs (macOS, Windows, Linux) in a comparable way.

Perhaps another very specific question for users who run macOS Sonoma on Proxmox: What does the CPU specification in the VM configuration file look like? Mine looks like this:

-cpu host,vendor=GenuineIntel,+invtsc,+hypervisor,kvm=on,vmware-cpuid-freq=on

Thanks & Greetings, Andreas

 

[_gabriel]

afaik, cpu set to "host" passthrough all features the host cpu can. don't need to set others.

 

[Kingneutron]

Keep in mind that MacOS isn't really designed to run as a VM; Windows and Linux have had years to add code that helps with speed when they're running in a virtual environment

https://discussions.apple.com/thread/250646417?sortBy=best

https://threedots.ovh/blog/2020/12/macos-eula-licensing-restrictions-affecting-virtualisation/

https://apple.stackexchange.com/questions/91734/using-mac-in-a-virtual-machine-legality

Generally speaking, OSX / MacOS expects to be run on actual Apple hardware.

 

[penzelan]

Hello Kingneutron

Your comment is completely true and correct, and my question has been answered conclusively.

Users who want to run macOS on non-Apple hardware may want to compensate for the performance losses of pre-virtualization by using more powerful processors.

It remains interesting to see how macOS on Proxmox behaves on Apple hardware. However, I'll leave that to others - my curiosity in this regard is not great enough to "repurpose" my Apple hardware ;-).

Greetings, Andreas