For a general purpose system, this line of thinking makes sense. However, the desktop system in question was built to be daily driven and support some high performance code research, so it had to endure some serious loads for a desktop computer.
I went the other way and overspecced the CPU cooler and added some silent but high CFM capable fans on the system. The motherboard I got was able to adjust all fans depending on the system temps, so it scaled from a very silent desktop to a low-key space heater automatically under load.
Instead of undervolting the processor, I was using a tweaked on-demand governor on the system which stuck to lower power levels more than usual, so unless I was doing software development and testing things, it stayed cool and silent.
BTW, by 100%, I'm talking about completely saturating the CPU pipeline. Not pseudo 100% where CPU reports saturation but most of the load is iowait.
