Apple released a pair of EFI updates for their most recent Macs, addressing issues with sleep and Thunderbolt, as well as general performance improvements.
First, the EFI update for new 2012 iMacs:
This update is recommended for all iMac (late 2012) models. This update contains general performance fixes pertaining to sleep and Thunderbolt, and improves compatibility when using the 5GHz band in Wi-Fi.
Boot ROM or SMC Version Information: After Update is complete:
Build version: 010A.05
ROM version: IM131.88Z.010A.B05.1211151146
And another EFI update for Retina MacBook Pros:
About MacBook Pro Retina EFI Update v1.1
This update is recommended for all 13-inch MacBook Pro with Retina display (late 2012) models. This update improves sleep performance, enhances Thunderbolt router support, fixes an HDMI display issue, and improves compatibility when using the 5GHz band in Wi-Fi.
Boot ROM or SMC Version Information: After Update is complete:
Build version: 0106.03
ROM version: MBP102.88Z.0106.B03.1211161133
The updates are available through Software Update for eligible Macs, as well as direct download from Apple’s support site using the heading links above.