86Box on the M6 Mac Mini Emulates a 600MHz Pentium II and Voodoo 3

A review on nyaa.sh has emulated a late-1990s PC on Apple's new M6 Mac Mini. With 86Box the machine runs a 600MHz Pentium II and an emulated 3dfx Voodoo 3, 20% above the top stable clock the same setup reaches on a base M4 Mac Mini.

Why the job lands on one core

86Box emulates an old PC at the hardware level, so CPU timing, chipset behaviour, graphics, sound and disk controllers all matter to getting period software to work correctly. That accuracy is expensive and almost all of it lands on one host thread, so what counts is single-core speed and how long it can be held.

86Box reports emulation speed as a percentage of its target. 100% means the host keeps pace, and anything less is a real problem, because sound hardware is fed in real time and brief dips are audible as dropouts. Version 6.0 improved CPU emulation on ARM hosts and added an ARM64 JIT recompiler for Voodoo graphics.

The test setup

The tests use a custom build from the 6.0 commit (build 9001), with Pentium II Deschutes frequencies extended in 50MHz steps up to 800MHz; the AT bus stays at 8.33MHz. The emulated machine is fixed: a Slot 1 board, 256MB of memory, a Voodoo 3 with 16MB of video memory and Windows 98 SE.

Each run loads Cinebench 2000's CPU test while Winamp 2.76 plays a 16-bit 44.1kHz PCM WAV in the background. A run passes only if emulation speed stays at 100% with no audible dropouts.

A stable 600MHz on the M6

The base M4 Mac Mini holds 500MHz and fails at 550MHz. The M6 passes 550MHz and 600MHz: at 600MHz it held a flat 100% through both Cinebench 2000 runs and the 3DMark 2000 SE demo, about seven to eight minutes of testing. At 650MHz a couple of audio underruns appeared, so 600MHz is the stable result, 20% higher than the M4.

Cinebench 2000 scores rise with the emulated clock, from 7.02 CB at 450MHz to 9.28 CB at 600MHz. A physical Pentium II 450MHz scored 4.35 in an Ars Technica forum thread; the author calls that no controlled comparison and does not know why the gap is so large.

On the host side, 86Box uses two performance cores averaging around 4,483MHz at 450MHz and 4,710MHz at 600MHz, peaking at 4,788MHz, while total CPU usage never passes 26%. The M4 keeps its busy cores near 3.7GHz. The author calls the cheapest new Mac desktop an unusually good machine for this and places the virtual system in Pentium III territory.