Drop to a slower emulated processor.
If you want to use Windows XP instead of an older OS on the slower processor make sure you only install what is necessary including what service Pack is actually needed and do all the Windows tweaks.
If the games don't need pcem and work fine on the host or via virtualization not emulation then use that.

Jazz jackrabbit 2 worked fine on Win11 the last time I played

Otherwise consider using Win98 for your machine. A slower CPU should also be fine, like a Pentium MMX

512 MB is enough RAM to run Windows XP and nothing else because all it does is constant disk swapping. Up the RAM to 3 GB which is XP x86's memory limit. There was a PAE hack that allowed XP to access more RAM but I never tried it. Try installing XP Service Pack 2 since that's lighter than Service Pack 3 (It's what I used when I had a Pentium II 400MHz desktop).

Norton Commander wrote on 2025-02-23, 12:20:

512 MB is enough RAM to run Windows XP and nothing else because all it does is constant disk swapping.

More like 64 MiB.

Up the RAM to 3 GB which is XP x86's memory limit.

In PCem, the Gigabyte GA-686BX is limited to 512 MiB of RAM. Editing the c0nfiguration file to specify 3 GiB of RAM causes a crash when the machine starts up.

you should try 86Box! I have been having a blast with it. Only downside is that on Mac the 3dfx implementation can be buggy. It's like a modern and more updated for of PCem

The 3Dfx implementation is buggy on all the supported host platforms, and the bugs are mostly inherited from PCem* - we have, if anything, fixed a number of them already, though several remain to be fixed.

* I could be wrong and there could be regressions introduced by 86Box itself, I certainly can't exclude that possibility.

Closed, topic annoys me and the "issue" has likely been solved.
This is not a thread for all PCem issues, comparison of emulators, recommendation of other emulators or issues that do not involve the op.