> I'm sorry to trouble GIMPSers with what might be more of a computer question. I > am using an Athon Thunderbird 1.3GHz and 256 MB of 133 MHz (DDR) Ram. > > My computer has always emitted a high pitched squeaking noise when processes > like GIMPS start, and also when I do things like use the scroll wheel of my > mouse etc. Recently the computer started hanging randomly on certain tasks (not > GIMPS). After having taken the RAM down to 100MHz the high pitched squeak and > the hanging has stopped.
I would guess power supply. Switching power supplies operate the transformer in the tens of kilohertz range, and when driven hard magnetostriction can cause the iron core to be mechanically coupled to the electrical signal in the windings, hence the high pitched squeal. This is also why TV sets (especially older ones) emit a high pitched whine that to some is almost unbearable while going unnoticed to others. By declocking your RAM you reduced the load on the power supply. The fact that you were experiencing instabilities further indicates an overworked or poorly designed power supply. If it's a cheap or underpowered unit, I would try replacing it and see if the noise continues. Cooling fans can also do this, since the 12V output of the power supply is poorly regulated. When the FPU powers up to run Prime95, the current draw from the PS increases and the 12V supply droops, and you can often hear the fans' speed change. Brian _________________________________________________________________________ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers