Monster Hunter Portable 3rd HD VER

[TheDax]

Please don't mention downloading ISOs/PBPs again in this thread, thanks.

Anyway, as far as slowdown goes, is it VPS slowdown or FPS slowdown?

If it's VPS slowdown, that means your PC/device isn't keeping up with the demands that the game needs. HD Remasters are more demanding than their regular PSP counterparts.
If it's FPS slowdown, there's likely a timing bug. Try the CPU Speed lock option; a couple people back on page 4 or 5 said a speed of 666mhz helped the FPS slowdown(keep in mind this will make the game even more demanding).