Alright... Here are some of my results from playing around with the emulator. All of this was done at 275mhz... I used frame skip 2 so much that you might as well figure it was on every game
Baulders Gate - Dark Alliance
gpsp3: Very fast and almost full speed but I found a slight graphic error in game when you hit start to go to the menu.
gpsp3_fast: I did not see any noticeable speed increase but the graphic error when you hit start was still there and slightly worse.
Bomberman Max 2 Red
gpsp3_fast: Slow menu but the game seems playable.
Castlevania Aria of Sorrow
gpsp3_fast: Bios trick needed to get working. Seems fast until enemies come up and then slows down to a slightly unplayable speed for me.
Castlevania Circle of Moon
gpsp3_fast: Slow start menu but in game menus are fine. Enemies on screen slow down the game again and the catacombs is a major slowdown.
Final Fantasy Tactics
gpsp3: Slow and not playable
gpsp3_fast: Slow but possibly playable for someone with more patience than me.
Final Fantasy 1 & 2
gpsp3: Menu very slow but playable in game. It is slightly faster than Final Fantasy Tactics but I wouldn't play it till a speed increase.
gpsp3_fast: Crashes after Square logo
Final Fantasy 4
gpsp3: Needs bios load trick and then is slow but somewhat playable. About the same speed as Final Fantasy 1 & 2.
gpsp3_fast: Crashes before Square logo without bios load trick then crashes after the Square logo with bios load trick.
Mario Advanced
gpsp: Loads with bios trick to get the message: Save data corrupt.
gpsp_fast: Same as gpsp.
Mario Advanced 2
gpsp: Selecting Super Mario World restarts the rom. You can play classic at frame skip 2, not at full speed but you can kill some creatures.
gpsp_fast: Super Mario World still resets rom. The classic version is a bit faster than the gpsp version but not full speed.
Mario Advanced 3
gpsp: Yoshie's Island restarts rom. Mario classic still slow but playable.
gpsp_fast: Yoshie's Island restarts rom and Mario classic is slow but playable. Slightly faster than gpsp.
Mario Advanced 4
gpsp_fast: Fast enough to be enjoyably playable
Mario and Luigi - Superstar Saga
gpsp: Needs no bios trick and playable.
gpsp_fast: Needs Bios trick to start. Selecting Mario and Luigi seems to crash rom but it could just reset the rom and with no bios trick crash.
Mario Kart - Super Circuit
gpsp: Slow but playable
gpsp_fast: Adds speed but the cars tend to flicker in and out. Same thing seems to happen with Spyro - Seasons of Ice on gpsp_fast
Mario Party
gpsp_fast: Slow but playable... I didn't test this on gpsp because the opening made me want to shoot myself.
Mario vs Donkey Kong
gpsp: Emulator crashes even with bios trick.
gpsp_fast: Emulator crashes even with bios trick.
Monster Rancher
gpsp_fast: Seems almost full speed. I've never played this so if there is a point in the game where you can walk around I didn't test this. I played up to getting a monster.
Monster Rancher 2
gpsp_fast: Same as Monster Rancher
Pokemon Red
gpsp: Works but too slow to enjoy
gpsp_fast: Still slow but playable
Pokemon Green
gpsp: Seems faster than Pokemon Red in gpsp but still not playable.
gpsp_fast: About the same speed as Pokemon Red
Pokemon Emerald, Ruby, and Saphire (all 3 games were the same)
gpsp: Slow and unplayable
gpsp_fast: Slight speed increase but still not playable.
Spyro Seasons of Ice
gpsp: Slow but playable
gpsp_fast: Faster than gpsp but when Spyro moves around both he and other creatures around him tend to flicker in and out.
Spyro Seasons of Flame
gpsp: Slow and not playable
gpsp_fast: Still slow and not playable but no graphic errors like in Seasons of Ice
Spyro - Attack of the Rhynocs
gpsp_fast: Slow but playable and no graphic errors.
Just a quick note, when I say the rom crashed I mean I can still go into the gpsp menu and re-load that rom or load a different rom... If I say the emulator crashed that means I could not go into the gpsp menu and had to restart the gp2x. Also it seems if I accidently exit the gpsp I need to restart the gp2x before the gpsp menu will work. Same thing happens if I try to go from gpsp to gpsp_fast.
Hope all this helps! I sure hope a new version was not released as I was typing this