You will need a CPU with at least SSE4.1 to use macOS High Sierra/Mojave.
It's somewhat amusing to see an Apple OS behaving nicely with an emulated modern CPU connected to 20-year-old PC hardware:
https://en.wikipedia.org/wiki/Intel_440FX
Incidentally this is also how some software detects it's inside a VM --- physically impossible hardware combinations. A real 440FX doesn't support more than 1GB of RAM. Also interesting to note that it was a predecessor of the famous 440BX which was highly popular shortly before the turn of the century.