Hello everyone. I own an iMac 21.5 " mid 2011 that mounts an Intel Core i5 2.5 GHz processor. In" About this Mac "there is nothing else written. Searching the net I found some other information: CPU: Intel Core i5 ( "Sandy Bridge") / CPU Speed: 2.5 GHz / CPU Cores: 4). It is therefore a second generation "Sandy Bridge". I think it could be the i5 2400 S (January 2011) or the i5 2405 S (May 2011). Can someone please tell me exactly which one? Thanks