Quick update for an old post on an even older system. I purchased a Xeon X5470 (10x multiplier, Socket 771, 12MB Cache, Quad Core) for dirt cheap on Ebay. Applied 771/775 mods to the CPU/Socket, updated the F2a BIOS with Xeon Microcode and installed the X5470 in my GA-P45T-ES3G. Runs perfectly at 4GHz (FSB 400) and Prime temps max at 68C (air cooled). Prime stable for 24 hours. Lightning fast (for me).
MCHCore Voltage: 1.3
All CPU power saving features are ENABLED in BIOS
Memory: Crucial Ballistix DDR3 1600 8-8-8-24
Note that the Xeon E5450 also runs great on this MB at 3.6GHz (400 FSB) with the same 771/775 mods.
Note also that some GA-P45T-ES3Gs will achieve FSB 400 and some won't. I have one that does and one that doesn't. Need good Northbridge cooling to achieve stable FSB 400. Good copper Northbridge heatsink and Arctic Silver 5 will do the trick.
Edited by deeveedee - 10/26/15 at 12:25pm