There is some strange speedup occasionally, especially when some enemies die (which could even be normal, this is my first FF7 playthrough ever), but the rest of the fight doesn't look like a power point slideshow anymore.
Depending on model complexity, the speed-up after killing off an enemy could be "normal," especially if there are a lot of enemies involved. I actually have the same GPU as you, though I'm playing within a VM rather than bare metal, and usually only notice slow-downs when a ton of people are standing around (Cloud being cornered by Shin-Ra goons during the opening mission, the team milling around in the hotel at the Golden Saucer, etc). Other things you might try out:
- Check your resolution settings in the 7H workshop. As I alluded to earlier, 1842x1014 and 1352x1014 are numbers I've never seen before, and while 1352x is a 4:3 ratio, 1842x isn't, and that might be causing extra GPU load trying to scale down.
- [00000000] GLITCH: Unable to turn on vsync >> Turn off vsync and see if that's causing delays even though the driver wasn't able to activate it
- Make sure there's only one instance of the music and direct folders in the 7H configuration. Recent RC builds have had a habit of adding gobs of them.