Apple posted a series of software updates overnight, all of them aimed at improving stability and performances of the new iMacs, MacBook Pros and Thunderbolt, the technology introduced in the MBPs back in February. The biggest update is for the early 2011 iMacs, which got an updated version of 10.6.7 with bug fixes, performance and security enhances. More specifically, the update improves the reliability of Back to my Mac, addresses Mac App Store bugs, improves Thunderbolt support and addresses other issues with graphics stability and 3D performances. It's a 382 MB download. Another update for the iMacs -- an EFI update -- "includes fixes that improve performance and stability for Thunderbolt."
The MacBook Pros received updates, too. The MacBook Pro Software Update 1.4 improves Thunderbolt, external display support and 3D performances, whilst the EFI update 2.1 "includes fixes that resolve an issue with Turbo Mode in Boot Camp, and improve performance and stability for graphics and Thunderbolt."
You can find all the updates in the Software Update panel on your Mac, or by following the direct links below.