The only other PSP emulator that's realistically usable/advanced enough to run commercial games decently is JPCSP, but it uses OpenGL as well, and has even higher system requirements than PPSSPP. You can use the ANGLE-hacked build of PPSSPP if you want, but it's old and buggy from the screenshots I've seen. Just know what you're getting yourself into. 
4GHz AMD 3900X, 32GB DDR4 RAM, 6GB Nvidia RTX 2060, Asus Crosshair 7 Hero (Wifi), Linux
How to ask useful questions: https://web.archive.org/web/20110214010944/http://support.microsoft.com/kb/555375
I'm not Dark_Alex, nor do I claim to be. Our nicknames are merely coincidence.
How to ask useful questions: https://web.archive.org/web/20110214010944/http://support.microsoft.com/kb/555375
I'm not Dark_Alex, nor do I claim to be. Our nicknames are merely coincidence.