i just tried it, it didn't fix the issue.

i've capped my framerate to 60 now. it seems to have not helped.
my framerate on these maps will usually stay around 10 to 20 whenever im not looking at the ground, but will sometimes fall to as little as 3.

In certain maps (grind and studio), whenever I look higher than about 40 degrees from strait down my frames will drop to around 4 to 12 per second. I've tried lowering all video settings to their minimum and un-sinking the games framerate but the issue persists. I've only played on three multiplayer maps so far, nuketown works normally.