I'm in the process of building up 8 new
Pentium 4 machines for work. I bought
genuine Intel boxed CPU's with fan and
heatsink.

I powered up one of the machines to start
loading software and got an cpu over-
temperature alarm almost immediately.

I removed the fan-heatsink assembly and
discovered that the copper cylinder that's
press-fitted into the aluminum radiator
was loose and had slipped back away from
the CPU chip. The cause was obvious, the
aluminum radiator had cracked top to
bottom when the cylinder was press-fitted
into place.

I called Intel and they are sending a
free replacement heatsink-fan assembly.