How fast is a macOS VM, and how small could it be?

In my review of macOS virtualisation on Apple silicon, I quoted performance figures that were obtained some time ago, and didn’t consider minimum specifications for a usable VM. Given current interest in running a VM on a MacBook Neo, I thought it would be worth examining these afresh, from macOS Tahoe.

How fast?

Using the same host, a Mac mini M4 Pro, this time running macOS 26.4.1 on its 14 cores (10 P + 4 E) with 48 GB RAM and a 2 TB internal SSD, Geekbench 6.7.1 scores are slightly faster, on both the host and a guest given 5 virtual cores and 16 GB of virtual RAM:

single-core CPU VM 3,855, host 3,948

multi-core CPU VM 13,222, host 23,342

GPU Metal VM 106,896, host 111,970

Neural engine CoreML VM 5,291, 8,577, 6,877; host 5,973, 41,251, 56,616

The last of those gives single precision, half-precision and quantised test results, in that order.

Comparing CPU single-core figures, the VM runs effectively at 98% of the speed of the host. Comparison between the multi-core CPU results is difficult, as the host has more than twice the number of cores, although four of them are E cores. However, given that the host has twice the number of P cores alone, the VM appears to perform rather better than the host on this test.

GPU performance isn’t quite as good, with the VM delivering performance of 95% of that of the host, when the latter isn’t contending for the GPU as well.

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