There were problems with early P4T533 motherboards. The problems
reportedly involved the switching power supply on the motherboard that
supplied the Vcore to the CPU (although Asus never even admitted that
there were problems, much less what they were).
The problems got worse the more power that was required by the CPU; very
few people had any problems with CPUs of 2.4 GHz and below, and because
it's power requirements are by far the greatest, the 3.06 with
Hyperthreading encountered the problem most often, although the problem
had nothing to do with Hyperthreading per se and was often seen with a
2.8 GHz CPU as well.
The problem was fixed in the fall of 2002, beginning with October I
believe (it may have been November). The boards with the fix also have
a fan on the 850e chipset, but the fan itself, while helpful, was not
"the" fix (the P4T533-C motherboard had the same chipset, and never had
either the problem or the fan).
You can tell the date of your board from the serial number, which is on
a sticker on the parallel port printer connector. 1st digit is the year
of production ("2" or "3", 2002 or 2003), 2nd character is the month
(1-9, then A, B, C for Jan-December).
If you have the problem, you can RMA the board to Asus and they will fix
it. All of these boards are still under warranty (they have a 3-year
warranty, and were first produced in 2002).
The P4T533 motherboard is a VERY good motherboard, providing, of course,
that you have one that works.