Who needs water or other forms of extreme cooling for overclocking on the ASUS P5B Deluxe WiFi-AP motherboard? Based on my experience so far, the answer is nobody. SImply disable/enable/disable PECI a few times!
To summarize my experience to date (all temperature readings are at idle using Everest Ultimate): Before overclocking and PECI disabled, CPU temperature was at 37C. Overclocking to 3.0 GHz raised the CPU temperature to 44C (with PECI still disabled). Overclocking to 3.2 GHz further raised the CPU temperature to 49C (with PECI still disabled).
I then disabled PECI and CPU temperature at idle dropped to 39C (still at 3.2 GHz overclock). A comment was posted on this blog (since deleted by the author) that disabling PECI again did not change the CPU temperature back up, but instead remained at the same temperature when PECI was enabled. Another post in the ASUS Forums indicated that disabling PECI further dropped the CPU temperature to the 22-27C range!
Of course, I decided to do my own test and disabled PECI on Nighthawk. Guess what? I'm still overclocked at 3.2 GHz but my CPU temperature at idle dropped down to 27C - a drop of 12C!
Note that the temperature of both CPU cores are still around 56C compared with the previous 54-55C readings.
Based on these information, I do not believe that enabling or disabling PECI has any effect on the CPU temperature unless you have case fans attached to your motherboard.
But obviously, there's a problem here somewhere. I suspect the problem is with BIOS Version 0804 which I am using.
I quickly checked to see whether the PECI setting had anything to do with the drop in Nighthawk's 3DMark06 score. It did not. The score remained the same; the BFG Nvidia is still under-performing at 3.2 GHz overclock compared to 3.0 GHz overclock of the Core 2 Duo E6700.
Speaking of overclocking, Tom's Hardware has the 2nd part of their Overclocking Guide: Suggested Components & Settings.
Tom's Hardware also has a recent article titled "The Southbridge Battle: nforce 6 MCP vs. ICH7 vs. ICH8" which contains useful information about the ICH8R controller.