I understand that you will like to downclock the processor to lower the power consumption and temperature.
First, you are right, this is not very common for gamers, but this question we do get it sometimes.
In regards to your inquires, the options required to lower the processor multiplier and frequency are in BIOS under the performance tab, unfortunately Intel(R) does not offer support on how to modify them as we don't recommend customers to change the factory specifications for the processor or motherboard.
Intel(R) on the other side does understand that we need to keep the power consumption to a minimal and that will lower the fan noise and temperatures. Your processor is configured with a feature that is called the Enhanced Intel SpeedStep(R) Technology (EIST) that will downclock the processor on its own when it is not under heavy load and will go way lower than what you may think. IF you set it manually to a certain multiplier, the processor will run at that frequency all the time but the Enhanced Intel SpeedStep(R) Technology will keep the processor frequency low until you need the performance then it will go up to its rated speed and even more with the Intel(R) Turbo Boost that will overclock the processor if required.