While you'll probably run out of memory first, there's the enormous overhead of running qemu's translation, too. Using QEMU to emulate x86 on my POWER9 system, I get... roughly the performance of a 2001-2004 pentium processor, and the host cpu is running at 3.8GHz and comparable speed wise to a 2018ish intel processor.
In spite of the author's insistence, I don't think Cosmopolitan is really usable on anything but x86, the QEMU thing is more a cute proof-of-concept. For very simple programs I guess...
