This is a
cooler made for low-profile cases - rack-mount servers and microATX/FlexATX
specialty machines like the Book PC. Despite being a conventional fan-on-top-of-a-heat-sink
design, the PAL15's total height is only about 26mm, from the CPU contact
point to the top of the screw heads. The super-thin fan draws a couple of
watts, which is on the high side for a low-profile unit; power draw doesn't
directly correspond to air moving effectiveness, but there's a strong connection.
In its first test, the PAL15
set a new record for awful performance, with a heater temperature well over
boiling point. But that was because of the little plastic feet on the base
of the cooler...
...which
were Alpha's way of making sure these coolers behaved themselves on the
then-new FC-PGA Socket 370 chips. The feet work fine on a CPU, but the copper
piece on the top of my heater wasn't quite thick enough to make contact
with the cooler, and so only a little thermal grease connected it to the
heat source.
I dropped another spacer -
a suitably trimmed piece of thin aluminium stock - on top of the copper
spacer, to bridge the gap. Now the PAL15 scored 1.06°C/W.
Considering that it was working
with one more thermal junction than usual, that's a particularly good result
for such a teeny cooler. I tried the second spacer out on other coolers,
and it caused at least a 10% thermal resistance increase; factoring that
in, the FC-PAL15 would manage about 0.96°C/W.
For $US30 or so, the PAL15's surprisingly
capable, for its size. Not much good for overclockers, but a big advance
over anything else this size.
