The Pentium IV Denormal problem relates to how the CPU processes very, very small numbers.

As I understand it, when the CPU has to perform operations on small numbers, it switches to a 'high precision' type of mode. As you might expect, this 'high precision' takes more processing power. Now, when you think about it, very quiet audio is really just a succession of very small numbers, and when you apply affects, etc to audio what you are really doing is performing calculations on these small numbers.

You can see where I'm heading with this. The problem is that when Intel designed the PIV, they designed it so that the 'high precision' mode kicks in at a relatively much higher level than was the case with the PIII. I say 'relatively', because in reality these numbers are still so small as to be inaudible. This means that, for software that does not take this into account, the PIV CPU actually has to work harder when there is a quieter signal (or silence) than when there is an audible signal.

Whether this is a bug or not is semantics - it was by design on Intel's part, but seems to have had undesirable and possibly unintended consequences. In any event, it was the chip that changed, not the software. That said, the only solution is to change the software.

The best fix is to get the software developer (it's typically plugins that exhibit this problem - especially free ones) to release a patch that changes the treatment of these small, inaudible numbers. There are also plugins around on the web that deliberately insert some noise into the signal path to boost the signal out of the problem range. I hear conflicting reports as to how successful they are in solving the problem.

As to life on Mars, I'm still working on that one...

Hope that helps,

Mark