What is the problem? The disk access bug. Now, for those that will argue--it isn't a bug, well, per tech support it is.
They just don't know exactly what it is.
What happens is framerate will be okay but if I turn my mech to look in particular directions, my SSD will then go nuts and start caching all sorts of stuff and my framerate will... "lock up" i.e. I get to look at a pretty picture for several seconds and then it will start animating again after teleporting me. Some of these locks can be five to ten seconds long. Others are a second or two.
Any of these locks are annoying.
On some drops the locks occur every few seconds. On others, only when I look at either teams spawn (mainly the southern, lower spawn in the bottom corner edge of the map of that spawn).
Now, I don't have a great system, a Q9450, 4 gigs ram and 2x 260 GTXs. Thing is--it isn't me. A clanmate of mine has a i5 system (super fast), 16 gigs ram and the absolute top of the line ATI card right now. He also gets it! The only difference with him is that it drops to 4 fps and he's porked all round periodically like me.
This points to one possible culprit--video buffer caching issues with GPUs. Why? I got rainbow textures on maps on this map once. Other than that--I dunno.
Things I've tried:
1. Latest drivers for GPU/dx/etc etc.
2. Turning off Ambient Occlusion
3. Turning down detail for ambient related stuff in options
4. Manually disabling SLI for MWO
5. Setting physx to 2nd gpu
6. Deleting shaders folder (over and over)
7. Reboots
8. Pull hair out (I'm not a CPA so I don't want to go bald yet

So, I'm stuck. I have multiple clansmates with the same bug. Everyone agrees the map didn't use to do this. It is now doing it on all maps to a limited extent but mostly--River City.
Who else is getting this? Anyone know of a fix? Other that are getting it--have you reported it?
The bug needs to be stomped out. It is ruining the game now for me. I miss the silky smooth framerates of months ago.