People who have purchased Call of Duty: Black Ops on Steam are getting a double dose of patchy goodness this weekend. Two new automatic updates have been released, one for multiplayer and one for single player.
Both patches include improved CPU performance and fixes for ADS lockups that occur when pressing shift-TAB to bring up the Steam overlay or while holding shift as a sniper. There are also improvements to zombie mode matchmaking.
The multiplayer patch also includes server browser bug fixes and a fix for a crash that would occur when viewing leaderboards when you have more than 99 friends.
You can read the patch notes here and here.