Intel manufactures a large wafer of semiconductor material, which is then sliced up into pieces to make their CPUs. Due to standard margins of error caused by everything from humidity to gravity, the quality of the material varies over the surface of the wafer. When they build the CPU, they have to test it to see how good the quality is. The impurities and imperfections cause the CPU to run at higher temperatures, so they name the CPU based on its quality. If it tests extremely well, they program it to be a Core i7 965 CPU. If it doesn’t test as well, they program it to be a Core i7 920 CPU. This process is called “binning.” This doesn’t mean that the 920 CPUs are low quality…each CPU is thoroughly tested for the speed at which it will be running. I could even speculate that since we don’t see a supply shortage on 965 CPUs, that they have a surplus and are likely using chips that qualify as 965 to make 940 and 920 CPUs at times.
The point, however, is that each “bin” has some variation to it. If you have a CPU that just barely made the cut to be called a 940, it will run quite hot as a 940. If it just missed the mark to be a 940, they call it a 920 and it will run very cool as a 920. In practice, we see as much as a 10-20C variation in temperature per CPU when cooled with an Intel stock cooler. That’s a big difference! Again, that doesn’t mean that the hotter CPUs will not work just fine, but it does mean that it is very difficult to answer the question: what temperatures are normal?
