>>409968929
>suddenly drop to 10fps for no reason
You wouldn't happen to be opening and closing the steamvr overlay or something, would you? Opening it lowers the supersampling way down and then closing it returns it back to normal supersampling. Something about that switch causes it to fall behind in rendering frames and just never catch back up. Whenever that happens to me I find looking at everything in the instance helps but it's all just pigeon superstition.