This miiight help yer. I don't fully understand how it does but from what I've read it mainly shift most of the processing from the CPU to the GPU. I'm still running off low-medium settings and had to reduce my rendering distance but I average 20-40 FPS depending on how much is going on in my screen.
http://forums.station.sony.com/ps2/index.php?threads/ultra-settings-improved-my-fps.59955/ --- "You must gather your party before venturing forth" "Go for the eyes Boo! Go for the eyes!"
you could try tweaking the user ini files to the extreme. For instance i've removed all the shadows, crass effects and whilst i get a performance boost, it isn't a lot during hectic fights. --- error: no errors found
Turn shadows off in useroptions.ini. Do this by changing shadow quality to 0. In game, turn down effects and particles to low, terrain to medium or low (I prefer medium because low provides no noticeable difference in FPS). Also, if you're really desperate, turn the render distance down. Default is 4000. Under 2000 it begins to look like crap, but it helps FPS a bit. Not so much in large battles though. I notice when you drop below 30, you drop below 30, period. Lowering verticle FOV can also help. Other settings should be largely determined by your GPU.
The game runs like crap though. Mainly because it's so CPU bound. It can run on any reasonable GPU nowadays, heck, my IGP in my laptop gets like 25-30 FPS on minimum with nothing going on (only time I'm GPU bound). It's all CPU. And honestly, the only CPUs that really run it well are modern i5s/i7s (sandy bridge i5 or better). AMD CPUs run it horribly, as do lower end intel CPUs and even the old core 2 quads. I honestly wouldn't recommend playing it on anything below, say, a Q6600. You're up a creek if your CPU is weaker. --- Desktop: Phenom II X4 965 | 8 GB DDR3 | GTX 580 | 1 TB HDD | W7 | 650W Antec | 1600x900 Laptop: A6 3400m | 4 GB DDR3 | HD 6520g | 500 GB HDD | W7 | 1366x768