I just had this now - It was similar in a way to the old server-bugout when Atalses died (back in very early CB), it happened in River City, right near then end, something like 9-8 score, most mechs dead - normal game up till that point, then Boom; FPS went down the toilet and it became almost impossible to move or to aim in anything even resembling a straight line.
Game suddenly dropped to about 2-8 fps for me, and some of the dead spectators (who confirmed the same in chat).
My PC is pretty poor tbh, but as I saw it was confirmed in chat by some other players.
Phenom 965be, 8gb ram, with a an HD7870 card, nothing spectacular this side of the last half-decade, but it was a *sudden* and I'm sure triggered by an even in-game, which is why I likened it to the old Atlas server bugout (back then of course it was caused by the model's ragdoll when it died).
I run the AMD version of shadowplay so I'll go review the vid & see if it shows anything dodgy...
Edited by BigJim, 08 October 2015 - 11:34 AM.