Pentium 4 Hyperthreading problems?

A few weeks ago, I was having problems booting my main computer. I had problems booting an SMP kernels with Hyperthreading enabled in the BIOS (a more formal description of the problem is here on the Gentoo Forums). However, Windows XP Professional detected everything ok.

Seems that, for some odd reason, the culprit was loose cables in the back of the box.