An update to Team Fortress 2 has been released. The update will be applied automatically when you restart Team Fortress 2. The major changes include:
Source Engine Changes
Fixed server CPU spikes caused by compression of string tables and packets.
Added sv_netspike, sv_netspike_sendtime_ms, and sv_netspike_output convars for investigating server performance
net_compresspackets_minsize default value increased to 1024. This convar now also determines the threshold to determine when a "fragment" (logical game network message, before being broken up into network packets) is compressed.
Added vprof_vtrace and vprof_report_oninterval convars, and tweaked vprof_dump_spikes and vprof_dump_oninterval to reduce output
Team Fortress 2
Added the Robotic Boogaloo community update: http://www.teamfortress.com/roboticboogaloo/
Fixed a chat exploit that would cause other clients to timeout from dedicated servers