I know when a computer is really loading it makes sounds. Like a high pitched "nic nic click click" type of sounds. But rapidly. If you say it only happens when under streess. Then it sounds like that.
If thats the issue, i dont think you can do anything about it. My old compaq did that, and my sony does it also. When its really loading. My sony dont do it as loud as my compaq. But you notice it.
But if its REALLY loud. Then something is wrong. To me, it sounds like your HDD. Maybe your psu. I couldent really tell you unless i was there. But if you say its REALLY loud. Then i would try figuring this out.
Finished With TF.