I am upgrading some of the components on my 27" iMac. Here is my current system: iMac (Late 2009) Model ID: 10.1 (27" Retina Display 2560x1440p) CPU: Intel Core 2 Duo E7600 @ 3.06GHz, 3MB L2 Cache, 65W TDP, 1066Mhz FSB GPU: ATI Radeon HD 4670M, 256mb HDD: 7200RPM SATA, 1 TB Memory: 4GB, 1067Mhz, DDR3 The components to be added: CPU: Core 2 Quad Q9550S 2.83 GHz, 1333Mhz, 12MB L2 Cache, 65W TDP, 1333Mhz FSB GPU: AMD Radeon HD 6970M, 2GB HDD: SSD, 250GB (Installed in DVD Drive Bay. SSD as Master with OS/Programs) Memory: 16 GB, DDR3, 1067 MHz I will add any notes/updates. I am benchmarking the entire system with multiple programs pre upgrade and will also benchmark again after for comparison. If anyone has some input/advice I'd be happy to hear it! I would like to increase the FSB of the logic board from 1066Mhz to 1333Mhz to fully take advantage of the upgraded CPU. If anyone has good instructions on how, I'd love to hear them. Thank you, Quick Update on logic board FSB: I believe the best route is going to be through the EFI. If anyone knows the best way to access the EFI or best program to use I'd be happy to know! I'm looking at different options right now. I might mount the EFI partition later this evening and take a poke around but I won't be changing any settings until I complete the upgrade. Want to explore all the options first. Update: I was easily/successfully able to mount the EFI Partition on my iMac last night using Terminal and the diskutil mount commands. Again, not poking to modify the EFI yet but it is there and accessible. If anyone has input on changing the logic boards clock speed through the EFI, I'd appreciate it. I will continue to read through this book, Mac OS X Internals: A Systems Approach and if I can't find help online, I'll try myself and post the results. Thanks everyone!