FFXII fps drops & framelimit

[karl_w_w]

some specs:
Win 7 x86
Athlon II X2 240 (dual core OC @ 3.4 ghz)
ATI HD 5770
4gb ram

From other threads I've read, my system should be able to play FFXII at a good speed, and generally speaking I get 60 fps, but occasionally my fps will drop down to around 40, usually in large areas (out in the desert or similar). I understand this happens, doesn't really bother me, but what does confuse me is that in about half of these situations if I toggle off framelimiting my fps will go back up to 55-60.

Does anybody know why that happens/have tips to prevent it?

It's not graphics related, I have my internal res set to 2732 x 1536 (double my screen), but the symptoms are the same if I have it set to native.
Speedhacks make little difference, just ~5 fps higher in the slow spots.
I've tried r3113, r3878, r4276 and they've all been identical.

Thanks

[refraction]

are you using speedhacks when this happens? They tend to give false FPS readings.

[karl_w_w]

It happens with or without speedhacks, always in the same situations (although If I turn up vu cycle stealing it says I'm still getting 60 fps but I'm definitely going slower, if you know what I mean)

[Shadow Lady]

Try disabling Vsync or forcing it off in the emulator and the graphic card's control panel and see if it does any better.

[karl_w_w]

I'd love to be able to try it with vsync on, but it just won't go I've tried in the settings and forcing it on my card, but I'm still playing with a tear that keeps appearing about 1/3rd down my screen.

[karl_w_w]

Interestingly, I disabled vsync and it seemed to help. Fiddling with that gave me an idea, I also disabled Catalyst AI, and (fingers crossed) the combination of the 2 seems to have fixed all my woes, so far I'm getting a near-permanent 60 fps.

Thanks guys.