Has the graphical performance of Aperture not felt quite as performance-y on your 2009 or 2010 Mac since installing Mac OS X 10.6.4? Apple's got an update for that.
Apple on Tuesday released Snow Leopard Graphics Update 1.0, a "stability and performance fix" for a few key applications running on Macs with Nvidia graphics cards. It addresses frame rate issues in Portal and team Fortress 2 on newer Macs with Nvidia cards. It also resolves a problem that could cause Aperture 3 or StarCraft II to become unresponsive or unexpectedly quit.
Affected Macs include: MacBook (13-inch, Early 2009), MacBook Pro (17-inch, Mid 2010), MacBook Pro (13-inch, Mid 2010), MacBook Pro (15-inch, Mid 2010), iMac (21.5-inch, Late 2009), Mac Pro (Early 2009), Mac mini (Early 2009), Mac OS X 10.6.4, Mac mini (Mid 2010), iMac (21.5-inch, Mid 2010), iMac (27-inch, Mid 2010), and MacBook (13-inch, Mid 2010).
The update is 69.2MB and is available in Software Update on affected Macs now.