At a certain point, no amount of speed hacks can make low end PC's run certain emulators. The general rule of thumb is that the system needed to run the emulator at a full to decent speed needs to be 3-6x more powerful than the machine you are emulating; and the Gamecube was more powerful than the PS2. The PS2 was the weakest of the 3 consoles that generation. 485 MHz x3, x4, x5 etc. This emulator achieves its higher frame rate and speed by a lot of speed hacks. Code shortcuts. This isn't necessarily a bad thing, but its compatibility can be just as bad and if there is a 32bit version it doesn't take full use of modern 64bit API's. Specific game fixes and speed hacks make certain problem games run, others not run. Emulating is not easy what so ever. Not that anyone said this, just a statement.
It's still a good emulator fork, but its just an alternative.