We should really have some kind of a State of the GP2X address thread or something .. just make a new one periodically, put it on the Wiki or something ...
GB Emulation: Full speed at default ARM920T clock (200 MHz) with Gnuboy2x
NES Emulation: Over 95% of full speed at default, Full speed with tiny overclock (GPFCE)
MegaDrive/Genesis: ~45-50 FPS on most games at 200 Mhz default clock, at 233 MHz+, nearly everything runs at 60 FPS .. at 250+ MHz everything is full speed (60 FPS) period.
SNES: Not quite full speed, but close, in most games. Runs smoothly with Frameskip 1 (30 FPS). Sound issues (fairly minor) and transparencies are either hacked to semi-work, or don't work. Otherwise quite playable.
PC Engine: Far as I know, full speed (60 FPS) at 200 MHz, with no sound so far. The PC Engine emulator WITH sound is not quite full speed but might be with a substantial overclock. Vobbo's emulator will probably run at full speed with sound soon, with a minor overclock or none at all. I believe it's called Hu6280.
Master System and Game Gear: Full speed at ~100 MHz (50% underclock of the GP2X's ARM920T) .. that's 60 FPS. Could probably run at full speed at 66 MHz or lower, too. Emulator is Alexkidd2x. New DrMDx releases have SMS/GG support but I've not tested it.
Pre-NES consoles e.g. C64, 2600 .. - Not used them, but I hear these run at full speed at default ARM920T clock, they should as they are quite simple and old hardware.
Atari ST - Not tried it but probably runs at full speed near default clock, same CPU type as the MegaDrive/Genesis and I do not believe any unusually demanding-to-emulate video or audio hardware.
Amiga - From what I hear, fairly slow but playable. Not sure which models are being emulated. M68000 based? ..
MAME - Depends on the game. Most games using an M68000 at 12 MHz or below, and a Z80 at 4 MHz or below, run at full speed with a substantial overclock, e.g. 266 MHz on the ARM920T. This is with 100% Video Clock and 100% Audio Clock. You can drop these to 80% normally though since the hardware does not usually utilize all of its capabilities for most of the emulated games ... most games just based on Z80s like 1980s arcade games will probably run at full speed closer to 233 MHz or lower. Maybe stock too.
Neo Geo MVS: Runs at full speed in games that do not use hardware scaling (most of them), that is to say, 60 FPS with sound at high quality (22050hz) with about 299 Mhz ARM920T clock. With 11050hz audio, runs at about full speed at 266 MHz too. Can run at full speed with sound off at 200 MHz as well.
