Higan is a cycle-perfect SNES emulator, and it's very single-core CPU-intensive. This is what the FAQ [0] says: Full-speed emulation for the Super Famicom base

Higan is a cycle-perfect SNES emulator, and it's very single-core CPU-intensive. This is what the FAQ [0] says: Full-speed emulation for the Super Famicom base unit requires an Intel Core 2 Duo (or AMD equivalent), full-speed for games with the SuperFX chip requires an Intel Ivy Bridge (or equivalent), full-speed for the wireframe animations in Mega Man X2 requires an even faster computer. Low-power CPUs like ARM chips, or Intel Atom and Celeron CPUS generally aren’t fast enough to emulate the Super Famicom with higan, although other emulated consoles may work. Work can't be split across cores (according to the FAQ) because that would compromise the accuracy of the timing. It may be that the PS2 has similar problems while being more powerful than the SNES. [0]: https://higan.readthedocs.io/en/v104b/faq/ https://higan.readthedocs.io/en/v104b/faq/