Here is the thing with a rated clock speed--It is a nominal value that is generated from an average number of measurements. So, for example if your CPU is rated at 3GHz, then some of those CPU chips will operate just normal at a higher clock speed, while some of those chips will not.
The trade off for overclocking is more heat, and possibly lower reliability.
Now to underclocking, if it works for you, then great. I personally can't picture any scenario where I would underclock, and only a handful of scenarios where I would overclock a CPU.
CPU's have a base speed and a top speed ( pre set) where the manufacture's test for long term reliability and optimal performance when needed. Most (especially those made for gaming) can be overclocked, but most manufactures don't recommend this, because yes they will operate fine in most scenarios, but it will lead to over heating issues eventually and a lower CPU life span.
The reason (which I thought I explained earlier) for underclocking it was the following.
Lower power use, Reduce the fan's from ramping up every 30 min or so (sounding like a jet ), And to make the computer absolutely quiet.
Since I use this for everything, and most importantly now, for a lot of music, Amazon HD, Spotify, stored files, youtube, etc.
I wanted it as quiet as possible. Plus cut down on the power it uses which is quite a bit. 150 or 200 watts (a lot I know) Remember it was designed for gaming. The underclocking has hardly caused any decrease in performance. Unless you were specifically looking for it, I don't think you would notice it. Now the temps are down dramatically on an average of 20c, which is huge. And the thing is dead quiet. Fans have not ramped up once, staying at a slow idle. And all while being able to do various tasks, and all while having my music being played.
I could see why some may not wish to do this. If they have like I had in the past, less powerful and less energy sucking machines. But for my situation, this underclocking was a no brainer. I still reap 95% of the performance (which is still better than a lot of laptops being used) and if anything have helped to prolong it's life cycle.
And with the energy saved, just means I can listen to my music even longer.
