Hi all I know this is a known issue, but I can't find the answer to it yet. I upgraded from 4.1 to 5.1, from quad to 6-core, my memory to 1333. My fan works continuously and loudly and my memory recognition remains at 1066. I know there is a conflict between my system SMC and my new processor SMC. Here is the image of things: Model Name: Mac Pro Model Identifier: MacPro5,1 Processor Name: 6-Core Intel Xeon Processor Speed: 3.46 GHz Number of Processors: 1 Total Number of Cores: 6 L2 Cache (per Core): 256 KB L3 Cache: 12 MB Memory: 16 GB Processor Interconnect Speed: 6.4 GT/s Boot ROM Version: MP51.007F.B03 SMC Version (system): 1.39f5 SMC Version (processor tray): 1.39f11 Serial Number (system): ... Serial Number (processor tray): ... Hardware UUID: ... What do I do?