Getting nasty hitching in performance

[Nicocat]

Periodically while playing in SP or coop (I'm hosting), I get these huge, one to one and a half second hitches in the game. Everything just stops, like it's trying to load something. There doesn't seem to be any rhyme or reason to it; it could be working fine in a huge battle, then hiccup afterwards while just running around a cleared area.

I have a Radeon 6950 with 13.3 catalysts, an i5 4670k processor, 16 gigs of RAM and the game is running from an SSD. I have absolutely no idea what could be causing this. I've been turning video options down little by little, to no effect yet. The CPU and memory usage are nowhere near maxed, so I don't think that's the culprit. Any ideas on how to even help debug this?

[Solais]

Post your log, as said in the FAQ, maybe we can see the problems there. Best if it's a log after you played the game.

[Nicocat]

Here's the log from the day: http://pastebin.com/p29vSQvS (it was a big log, too big for the comment system)

The .rpt file had nothing in it from this year, let alone yesterday, so I left it out.