This is the most interesting thing I've found. While reading these white papers.

Prescott SHOULD see a boost in performance over the Northwood in things like Content Creation and business apps due to the added L2 cache, but it doesn't! So much for taking steps forward with a new processor release. Take a close look at all of the benchmarks and how the Prescott is alot slower than the Northwood in almost everything.

This diagram represents what I believe is a big reason why. Compare the normal clock to the resultant internal clock. This new internal clock is what happens when you have the thermal monitor enabled. I believe those flatlines are when the chip is cooling itself down. As the speed of the processor increases the heat will also. I am very interested in seeing how it affects performance to bypass this feature. I've emailed Wesley @ anandtech and Kyle at [H] about looking into this further. They're the benchmarking experts, not me.

I believe that with this technology enabled everybody who posted a review of this processor and tested in a cooler environment will have seen better results than anybody who was benchmarking in a hot room. When the CPU reaches a certain temperature it will halt it's calculations for a certain period of time. This period of time can be set by using ACPI MSR's in steps of 12.5% from 12.5% to 87.5%. The lowest setting is best for performance while the highest is best for staying cool and chasing bragging rights for highest clock speed. If this ACPI setting is set high it could halt it's operations for a considerable amount of time. This will hurt performance but makes you get insane overclocks. All of you people out there in a Mhz battle make sure you max this out ;)