Unfortunately, when it comes to computers, spending extra money on parts to silence and/or prevent overheating that computer may not be an attractive option. Therefore, I am here to provide some options that are often not thought about.
Underclocking, in layman’s terms, is modifying the hardware to make the computer run slower than it is supposed to. Although this may not be a popular option, if the computer is getting really noisy and/or shutting down from overheating, this may be an option to consider.
How to underclock an AMD Phenom II and Intel Core I7: http://aprivatebeach.com/blog/2009/11/underclocking-a-amd-phenom-ii-x4-or-intel-core-i7/
Clean the computer
Another option is to clean out the inside if the BIOS is locked to under and/or overclockers. In many cases, noise and/or overheating issues can be solved by removing all the dust bunnies inside the case. The most vital components to clean are the CPU heatsink and the fans.
When I clean my computer, I take it outside and clean it there. This keeps the dust outside and not inside the house.
A video I found on Youtube. There are several videos on how to clean your computer online, but I find this one the best.
Set maximum and minimum CPU speed
Interestingly enough, Windows 7 and Vista has the option to control the CPU speed. http://www.vistax64.com/overclocking-cooling/238678-help-underclocking-plz.html. This will explain why my hardware monitor shows my CPU running at 25%(809 MHz) during idle times. It seems that it can also be used to determine the maximum speed the CPU is allowed to run. Therefore, fiddling with the BIOS may not be necessary.
As of November 11, 2009, it seems that the maximum CPU speed does not work. Setting the maximum to 50% does not limit the CPU speed to 50% of the CPU’s capable speed. Therefore, only the minimum CPU speed seems to be working.