Hi Folks, So after a buttock-clenchingly nervous first ever CPU upgrade experience, my 4,1 dual is now sporting a pair of 3.06 X5675s. Temperature appears to be lower than the original E5520 2.26s, with CPU A Diode sitting on 39c with an ambient of 29c. That could be due to newer thermal paste, I suppose. I eventually went with the Arctic MX-4 thermal compound, which seems to work nicely. One thing - although the firmware upgrade seems to have gone through (it's booting after all), and System Information is reporting it's a 5,1, the memory which was sold to me as DDR-1333, is only reporting in as 1066. Any suggestions to diagnose it, before I contact the vendor with a "what's up?" Cheers.