If you are looking to mantain the best CPU temp with least noise , GO H2O , Corsair has two nice units the , H-50 works good on 95 watt CPUs and the H-70 works good on 135Watt CPUs . I have one of each and they are great at maintaining temps no mater the load. I have A Overclocked Xeon that runs24/7 and stays 40 c under worst load never gets above 50 c.
Thanks for your reply! I do understand that there are good and bad cooling, but my question was that I want numbers on life time vs temp, so I can make a rational tradeoff. The general relation that lower temps = better is clear, but how the functional relation Lifetime=f(T) looks like is not so clear.
The reason is that in some embedded units, you simply don't have the choice to change the cooler. It is what it is, the option may be the reduce the FAN speed or so.
So the question becomes that of a compromise. Noise vs temp.
If I know how the statistical lifetime vs load temp looks like, I would be able to make that decision.
For example for one P8400, we experimented with dropping the FAN speed to improve noice, but temp went from 65 to 75.
I want to quantify, how much lower lifetime one can expect due to that, or due to getting the temp up even to 80-85.
The common reasoning that people replace their PC every 3 years or so is not the answer I need, since not all poeople od thta. Some embedded sytems or special purpose PCs can easily run for 24/7 20 years, or simply until they break down.
This is why I want to quantify the tradeoff. The only people that I can imagine that migh be able to answer this is intels own development/testing. So I was hoping to get some official responce from intel on this forum.
As simple as the question sounds it is very hard to give you a straight, definitive answer you want in an open forum.
The Thermal/Mechanical Specifications and Design Guidelines (here is one) http://download.intel.com/design/processor/designex/322167.pdf covers a lot around what you are asking.
Customer support can also provide MTBF data on the processor will also help you to make a judgement call. http://www.intel.com/support/processors/sb/CS-030116.htm
Processor class also has a major impact here. A Xeon server processor is designed for extended operation at high work loads which generally translates to higher temps. I have seen a number of the newer Green Servers delay fan ramping to maintain CPU temps in the 65-75 deg range.
So, I am not a lot of help either, but hopefully I have pointed you in the right direction.