I've been experiencing a severe performance hit since the recent patch that made some changes to the audio (11.155?). It only occurs when using my Bluetooth headset though. Frame rate falls to the teens making everything pretty much unplayable. No Bluetooth attached and it runs at a constant 60fps. Increasing the audio latency to several hundred ms does alleviate it a bit, but that's not really a tenable solution.
Are there any other settings I might try fiddling with?