Hi there, this is my first post so go easy on me! I did try to search first and didn't find anything helpful.
I currently have a Core 2 Extreme x6800 CPU in a Asus P5N32-SLI SE Deluxe board and Windows Vista (ok, after you've finished either laughing or growning, please continue reading) I performed a registry "fix" on my system to increase performance. The idea is that it allows core 2's (I think) to run properly under vista after being set up by an OEM originally. As a result speed step doesn't kick in, which means that the system is running at full speed, the downside being that now I've changed my machine to SLi It doesn't keep itself cool and the HSF is running at full speed constantly. If anyone here can either tell me how to undo it or just point me to the instructions on how to make it faster, I can disable it myself, just the Harrier jump jet on my desk is really getting on my nerves!

just do the reverse of the fix that you did. I am assuming you just chanegd a value in the registry yes?

Some where in your systems BIOS under the chipset setup, you should have a Speed Step(Intel) or Cool and Quite(AMD) that you can enable or disable. With it enable, the system will slow down and keep cool until the CPU is taxed. With it disabled, the CPU will run full speed all the time.
Also inside the the BIOS on certain types, you can set the CPU's maximum Temperature range.
On my system I have Cool and Quite disable and the Maximum CPU temperature set at 120 degrees F. The hottest I've seen my CPU get up to was 122 Degrees F.
When the CPU gets up to the 120 Degrees, the CPU fan speeds up to maintain the 120 Degree range.

Ummm... there shouldn't be a manual registry fix for vista on multi-core CPUs. I never had to do that for my Vista on my quad.

XP would have needed a reg fix, but SP2 or SP3 would have already fix that problem, if memory serves.

Try this: http://www.vista4beginners.com/power-management

Basically go into the bios and in the tweaker section set c1e and speedstep to enable Sounds ike you have them off, and also turn AINOS on and set it for 10 percent. Basically you will see speed step come on if you let it idle and it will automatically overclock when it feels it needs more power. With my setup i've been getting a auto overclock from 10 to 20 percent with out it being constantly overclocked. Currently i'm looking at 34'C and cpu fan running at 2600 under bios control. Using AI Booster to view right now.

ps

the only difference between your motherboard and mine is you have the deluxe

Thanks for all that, all of the power management features in BIOS are on already. I have a dual boot and XP seems to behave itself it's vista that locks to full speed...the other annoyance is that if I try to enable max power saving under vista which tries to turn the CPU down to half speed, the PC locks up and needs to be turned off on the power switch and then back on. I have to say though, I also have Vista 64 bit.
PS. As for AINOS, not a good plan, I have enough trouble keeping it cool as it is. I might have 4x120mm case fans set up properly, however the 2 8800GTX's and they generate a LOT of heat!