In case it hasn't been mentioned in this topic PCSX2 is more CPU dependent over GPU, while having a nice GPU is important I figure anyone who is having performance issues might want bring up what CPU they are using, I was a member / lurker over at ngemu for a period of time and most of the Mods and Support guys over there always brought up the importance of PCSX2 being more CPU bound then GPU bound.
Just figure for those striving to get this thing running perfectly should know this instead of trying to throw a monster GPU at the emulator like you would when maxing out the typical PC game, it's your CPU that is doing the bulk of work for PCSX2, so just keep that in mind.
Also for anyone interested in playing FFXII via PCSX2, you might be interested in checking out the FFXII IZJS translation patch which uses your legitimately owned copy of FFXII as a base for the text but has the gameplay improvements and tweaks that the International version has. Yes those wanting to experience FFXII for the first time would probably enjoy the game far more by jumping straight to the IZJS version from the get go. The improvements are worth it.