Vista - CPU upgrade, now cannot boot vista at all!

So, I recently upgraded to a phenom 9950BE from my "old" 6400+ X2, I have 8GB of RAM, 2 500GB HDD's in raid 0, and an 8800GTX. I updated the bios no problem, I can get the motherboard to post with the phenom. I'm actually on the computer right now, however "only" with 4GB of RAM in. If i put in the other 4GB of RAM the computer just powers down at the vista load screen. HEEELLPPPP!!!!!! This computer is my workstation and the 8GB is actually necessary.

Troubleshooting I have done:
-memtest on all RAM, all came up fine
-(I have a 1200W power supply, the power is clean and stable, no problem there)
-reinstalled vista with SP1 and the KB929777, no luck.
-I upped the voltage to my RAM from 2.1v to 2.175v, the NB from 1.3v to 1.325v, and the HT from 1.23v to 1.275v. It made somewhat of a difference as far as the ability to actually do some process intensive computing. But no change on the RAM.

I am at the end of my wits and just about to say to hell with it and buy a 790GX mobo and new vid card, but would prefer to sink the money into that a little later rather than right now.


Any help is greatly appreciated, Thank you!

So, the PC was working fine with the 8 GBs of Ram prior to the CPU upgrade? Also, are the 8GB's of Ram compatible?

you should run everything in the bios on stock settings when you do an os install.
and ran your ram at the manufacture specifications.

When i first installed the CPU, yes, I reset the CMOS and ran stock settings and nothing worked, upped the voltages and managed to get a little usability out of it, but nothing on the scale of showing any improvement or to resolving the problem.

Also, Yes the RAM worked great for almost a year before this with the 6400+, and is on the manufacturer's supported list and the motherboard is capable of 8GB. With the new BIOS it's even supposed to "support" 1066 MHz RAM, but mine is at 800 MHz.

Thanks

Got it figured out! talked to an assembly programmer friend of mine, he thought it sounded like a memory registry error and that I should check if my paired modules are in the correct slots (1&3, 2&4) sure enough they were not paired and I at least got a blue screen with 8GB. Then I happened to be scanning the bios for somewhere I may have gone wrong and found the "ganged mode" for the RAM. well some chinese programmer decided it would be an excellent idea to have the stock setting for Dual-channel memory to be disabled. I enabled dual-channel ganged mode and sure enough I'm runnin sweet! Thanks for all of your help!