I have a Dell R510 used for a SQl server. Can I go from E5620 to X5690? They are both in the same Intel Xeon 5600 series. But the i did not know if a X (Performance) is interchangeable E (Mainstream). If not then the fastest upgrade i can make will be to another E. thx Intel® Xeon® Processor E5620 (Current) http://ark.intel.com/products/47925 Intel® Xeon® Processor X5690 (Proposed Upgrade) http://ark.intel.com/products/52576 Intel® Xeon® Processor E5649 (Fall back Upgrade) (cant post link)