Yes there are patches and they improve performance as well so if you are on vanilla version then updates might help.
vanilla version??
okay, searched and got a update from v1.0.438.0 to v1.0.444.0 on tpb. but its 12gigs???? wtf?
CHANGELOG
* Added option to lower or disable Bloom effect
* Change Cover' action can now be mapped on a separate key.
* Country leaderboards are now in the correct language
* Weapon selector doesn't appear when point shooting anymore
* Pausing game doesn't skip cutscenes anymore
* Slightly improved general performance
* Performance improvements for MSAA and HBAO
* Fixed King of Chinatown behavior
* Disabled use of all DirectInput devices (as they are unsupported)
* The disguise parameters on Professional difficulties have been tweaked.
* Difficulty adjustments
* Displayed high scores are now selected from all difficulty levels.
* Fix for negative scores
* Fixed disappearing user interface on AMD HD 3650