I checked some temperatures tonight. Ambient temp and water temp were checked with my Micronta Indoor-Outdoor digital thermometer. CPU temps were logged with
Speedfan . The computer was warmed up with a 30 minute game of
Sven Coop, then left running at idle for 30 minutes.
I started another game of Sven, started logging with Speedfan, and measured water temperature in the resevoir every 2 minutes for the next 40 minutes until the computer blue screened.
No joy after a restart, BIOS was stuck on 'Detecting IDE Drives'. I've got a Zalman passive heatsink on the Northbridge chip that seemed too hot, so I let everything cool for a few minutes and it's working fine now.
Start of test
Ambient 25.0C
CPU 40.0C
Water 31.0C
End of test
Ambient 25.1C
CPU 45.5C
Water 33.0C
I hope this helps, duh_bing. I'm not sure of the accuracy of the onboard CPU temp sensor or the accuracy of the digital thermometer, so view the results with some suspicion. Let us know what you find out when you do the math.
Here's a chart of temperatures/time: