AMD recently released its Catalyst 12.11 Beta 11 driver, which features performance improvement in Far Cry 3.
Some new features of Catalyst 12.11 Beta 11 driver
•Improves performance in Far Cry 3 (up to 25% with 8xMSAA, SSAO enabled @ 1600p, and up to 15% with 8xMSAA, HDAO enabled @1600p) (AMD Catalyst 12.11 CAP2 must also be installed)
•Resolves a sporadic system hang encountered with a single AMD Radeon HD 7000 Series GPU seen on X58 and X79 chipsets
•Resolves an intermittent hang encountered with AMD Radeon HD 7000 Series GPUs in a CrossFire Eyefinity setup.
•Resolves image corruption found in certain DirectX 9.0c titles
•Resolve missing fonts issue in XBMC
•Resolves no video issue found in Media Player Classic Home Cinema when using full or half floating point processing
•Resolves stability issues found in the previous AMD Catalyst 12.11 Beta8 driver for Linux
•AMD Catalyst 12.11 CAP2 has just been released, and should be used in conjunction with AMD Catalyst 12.11 Beta11
◦Improves Far Cry 3 performance for single GPU configurations with AA enabled