And now, a show stopper, for me anyway...

[CharveL]

Interesting. I'd be inclined to agree then that it's something more fundamental.

Still, it seems tied to particle effects, and at least for me, happens the closer the effect is happening. You can really see the frame rate slow down in close explosions although the same can be said for some other more stable games too.

Anyway, I'd bet they are well aware of what is going and have decided to put their efforts into a better optimized engine than a band-aid for the existing one. Unfortunately, that will likely mean a lot more time and subsequent patching for the bug train that's sure to follow.