Apple has released several updates for the iMac and MacBook Pro.
The Mac OS X 10.6.7 Update for iMac (Early 2011) 1.0 (http://support.apple.com/kb/DL1383) is recommended for all early 2011 iMac models. It includes general operating system fixes for Mac OS X Snow Leopard that enhance the stability, compatibility, performance, and security of your Mac. It’s a 382.56MB download.
iMac EFI Update 1.6 (http://support.apple.com/kb/DL1380), a 6.1MB download, includes fixes that improve performance and stability for Thunderbolt.
MacBook Pro Software Update 1.4 (http://support.apple.com/kb/DL1382) includes fixes that improve graphics stability, address issues with external display support and 3D performance, and improve Thunderbolt device support. It’s a 132.69MB download.
MacBook Pro EFI Update 2.1 (http://support.apple.com/kb/DL1381) includes fixes that resolve an issue with Turbo Mode in Boot Camp, and improve performance and stability for graphics and Thunderbolt. It’s 3.06MB download.