Ok I figured out what the issue was (for me anyways...). It seems that some option that's applied with Ja++'s renderer menu completely kills the FPS and whatnot. I started the game with defaults and the latest Openjk, but not Ja++, then I put the menu settings as high as they could go, and entered a custom resolution in the console and restarted, no issue. I then started up the game with Ja++ and maxed out the settings in the renderer menu there, and when those settings were applied, the game ran terrible again. So after deleting the Openjk.cfg (defaulting the game basically) again I just set up the video settings with only Openjk running, then when loading up Ja++ I didn't touch anything related to the renderer menu, and everything works perfectly fine now, lol.