Underclocking Athlon64 X2 6000+ (desktop Board)

I "upgraded" from 32bit XP, to Vista x64. Now, my system is plagued with a mainboard that auto-throttles when its chipset hits 45C temps. As a result, until I can figure out how to get a little more cooling into it, I've temporarily underclocked my CPU to 2600mhz(x2) from 3000mhz. Or, at least, I -was- doing that, before Vista SP1.

Now, no matter what I set, or how I set it, it seems to get reset to 100% If I use Vista's own power scheme settings, I can make it run at 85% max 5% min, and it saves, goes a while, maybe 10 to 15 minutes, then I notice the system is auto-throttling again. I check, and sure enough, it's set back to 100% max, 100%min.

If I use AMD OverDrive, the same thing happens.. I set to 13x multiplier, and drop the voltage a bit. 10-15 minutes later, It shows my "Desired Settings" still, and they have to be re-applied.