I'm not sure how to go about fixing this, as it is happening randomly to a degree.  Up until now i've tolerated it, but it has become a little more then an annoyance.
 
I have my CPU OC to 3.45ghz.  I have speedstep disabled.  What happens is it runs perfectly fine at this OC, but if i have to reboot for whatever reason, it drops the multi to x6.  And requires atleast one reboot to fix.  It's weird because when i enter the BIOS it still reads 3.45ghz, and sometimes when i reboot from the BIOS it goes to the x6 multi again requiring an additional reboot.
 
I'm pretty sure i have all the necessary things disabled or enabled in the BIOS to theoretically prevent the multi dropping due to heat or lack of load.  However i may have missed something and was hoping someone can help me fix this.
 
I'm running a XFX 680i mobo BIOS version 6.00 PG from Pheonix Technologies, LTD.
 
Rest of my specs are i nthe sig.

Just making sure, but you did disable Thermal Control and C1E Halt State as well right?
 
I remember reading that the 680i had problems like this with the damn multiplier dropping and increasing randomly. Ebay it and get something else?

What CPU are you using?  I've also heard about such issues with 6x0 chipsets -- unfortunately, all too often, that's life with nVidia chipsets.

I'd have to double check Thermal Control, but halt state is off for sure.  And i would sell it, but unfortunately i bought an OEM Vista and i'd have to buy a new licence in order to swap mobos.
 
Mondoman, i'm using a q6600.
 
I'll go through my BIOS and write down all the settings for you guys to look at.

Ok i went through and copied everything that may have to do with this issue, and even somethings completely unrelated ><
 
Advanced BIOS Features
     CPU Internal Cache            [Enabled]
     Quick Power On Self Test   [Enabled]
     APIC Mode                          [Enabled]
     MPS Version Control for OS [1.4]
 
Advanced Chipset Features
     System Clocks          
          Spread Spectrum Setting
          CPU Spread Spectrum            [Disabled]
          HT Spread Spectrum               [Disabled]
          PCIe Spread Spectrum (SPP)  [Auto]
          PCIe Spread Spectrum (MCP) [Disabled]
          SATA Spread Spectrum           [Disabled]
     CPU Configuration
          Limit CPUID MaxVal          [Disabled]
          Intel Speedstep               [Disabled]
          x PPM Mode                      [Native Mode]
          CPU Thermal Control        [Disabled]
          C1E Enhanced Halt State [Disabled]
          Execute Disable Bit           [Enabled]
          Virtualization Technology  [Enabled]
          HPET Function                   [Enabled]
     System BIOS Cachable [Disabled]
Power Management Setup
     ACPI Function                    [Enabled]
     ACPI Suspend Type           [S3(STR)]
     Soft Off by PBTN                [Instant Off]
     WOL(PME#) From Soft Off [Disabled]
     PWRON After Power Fail    [Off]

Should i assume it's all right then?

I have a new question that i couldn't seem to find anywhere.  Perhaps i didn't look in the right places.  
 
Anyways in addition to the previous question of this thread, i have a Motherboard related question.
 
I've been worried about my motherboard temperature.  Recently i downloaded CPUID Hardware Monitor to check up on more then my core temps.
 
First off, i'm not sure which is my Northbridge temperature.
 
There's SYSTIN and CPUTIN.  If anyone know which temps those stand for, please enlighten me.
 
Anyway, i ran a prime small fft test to see what happens.  SYSTIN hit 60C and CPUTIN hit 62C after a couple minutes.
 
I have a Q6600 OC to 3.45ghz 9x multi.  If one of those temps is my Northbridge, is it acceptable.  If it is what is the limit, and if it isn't where should it be.
 
It's an XFX 680i.

 
I have an OEM copy of Vista Home Premium.  I swapped mobos a week or so after putting my new system together.  I had to call the Microblows phone number and talk to the support person with the very heavy Indian accent.  I got a new code as easy as pie.  I'm even planning on making another hardware change and I'm not anticipating any problems.
 

Yeah i recently looked that up, and learned what you explained.  I am quite relieved.  
 
I have fixed the random declock issue with a BIOS update.  Now to work on the temps.  I could either replace it, go water cooling, or remount the NB heatsink.  The latter i'm not too excited about doing since i'd have to remove my Tuniq in order to reach the NB.  And then put the sucker back on.

I just added a RAID1 setup with old 74 GB Raptor drives and installed my OEM copy of Vista.  I clicked on the "Activate Windows now" link under system properties just to see what would happen.  I was totally expecting it to fail and give the the phone number to call like before.  But, it worked!
 
Doesn't make much sense though...