Sadly I have to add to this unfortunately extremely popular post.
Here is my bit of data - hope someone eventually figures out what is causing these BSODs
My original setup:
CPU: Athlon 64 X2 5000 2.6 GHz
MB: Asus M2N32-SLI Delux
OS: Win XP Pro (32 Bit)
System default settings No OCing
This ran for 18 months - running games/streaming etc daily. No crashes ... ever!
My set up Summer 2010
CPU: Phenom X4 9850 Black Edition 2.5GHz
MB: Asus M2N32-SLI Delux (as above)
OS: Win 7 64bit
Upgraded BIOS to latest all default settings No OCing
This ran oroginally for about 3 hours before my first BSOD and then they happened more and more frequently over next 3 days until the system wouldn't even boot.
Returned to Windows XP Professional (32 Bit)
CPU: Phenom X4 9850 Black Edition 2.5GHz
MB: Asus M2N32-SLI Delux (as above)
OS: Win XP Pro 32bit
No OC-ing Cool and Quiet enabled
This ran for 6 weeks - rock solid no crash no BSOD - a very usable system but I wanted to install extra memory so I bought a new MB thinking that was probably the cause of my problems as the M2N32 is not certified for Win 7.
New System:
CPU: Phenom X4 9850 Black Edition 2.5GHz
MB: Asus M4A77
OS: Win 7 64bit
BSOD on install of Win7 - every time at exactly the same point during install (tried 5 times). I went back to my old MB and the Athlon 64 to give the following setup:
CPU: Athlon 64 X2 5000 2.6 GHz
MB: Asus M2N32-SLI Delux
OS: Win 7 64bit
And Win 7 64bit installed smoothly and the system has been rock solid and stable with 8 hrs use a day for 5 days now.
There you have it. Whenever there is a combination of the Phenom 9850 and Win 7 64bit I get BSOD but Phenom and XP Pro 32 bit and everything is fine - so I'm sure it's not the CPU.
I now have a Phenom 9850 and a spare MB so I may just try and put them together and install Win 7 32bit and see if that brings any joy but it doesn't look like I'm going to get to use more than 4GB RAM with my Phenom. Ah well!
Thanks everyone for their posts here - this the most informative information I've been able to find about this issue on the web. Hope someone figures out what is going on withthese Phenoms at some point and come up with a fix.