It's been a very long while since we've seen an update to the DaedalusX64 N64 emulator for PSP, but its developers recently stopped by the Wololo forums to let them know about their latest round of work. While the emulation itself is still finicky at best, the release notes indicate that there is at least a slight increase in performance over what we've seen in the past. In fact, if you happen to have a PlayStation Vita with TN-V, the frame rate you get may even wind up being a little smoother than on PSP. The source link below has a full compatibility list if you need it. As long as you don't expect total perfection, DaedalusX64's latest beta is well worth its legendary status in the scene.
DaedalusX64 [Beta R1909] (Signed & Unsigned Versions)
Here's the latest revision of DaedalusX64, which is R1909. This is this first update to the emu in approx. a year and a half (IIRC)! Both the Signed and Unsigned versions are included. The unsigned version has a customized EBOOT.
DaedalusX64 Official Compatibility List:
Any time you install a new version of DaedalusX64, make sure to "Reset Settings" under the "Global Settings" menu, or your emulation may be UNSTABLE!
Also, I've included the games' box-art images already pre-installed (which appear in the ROM menu selection screen of the Emu). So, no need to hunt those down and install them. I've also "PNG-Optimized" the images to take up less memory card space.
This does run on a homebrew enabled/eCFW Vita, and actually seems to run better on it.
Download: DeadalusX64 R1909 BETA