Hi, I have been running my 555 chip unlocked to a quad core in 32-bit Windows 7 for awhile now, I recently decided to upgrade to 4gb of ram. Once I installed 64-bit Windows 7, I was no longer able to boot past the splash screen. I have tried disabling ACC, updating my Bios, and increasing my cpu voltage. None of these things have helped me. Currently I'm only able to boot once I disable 2 cores. Does anyone have any suggestions on what to do, or will I really have to go back to 32 bit and render .75 gb of ram useless in 32-bit to keep an x4?
I decided to try booting 3 cores in 64-bit, and Windows launched successfully, cpu-z verifies that 3 are running although it lists my cpu as a phenom II x4. It seems like I may have to settle with an x3. I've never done extensive testing in prime95, so it's possible all 4 cores weren't functioning properly in 32-bit anyway.
I think you are right in your conclusion. If you were to underclock your CPU with 4 cores enabled, you might be able to keep 4 cores. I would go with the 3 cores though and overclock if you can.
I recommend testing with linx in addition to prime95.