Quote Originally Posted by balderrdash View Post
Tech support forums are exploding with lag and disconnect related complaints. Saw a few about the Naga mouse being borked with modifier keys as well. Think I'm going to hit some more Portal 2 and let this stuff calm down.
From Patch notes:

Added a network category to the new Options screen and included the two network checkboxes.

The Network category contains the options "Optimize network for speed" and "Enable IPv6 when available". "Optimize network for speed" will be enabled by default, and will send packets more frequently at the cost of higher bandwidth. The higher bandwidth may lead to disconnects for some players who have limited bandwidth. Players getting disconnected frequently should try unchecking this box.