Intel's higher heat output on the Prescott is partly due to
the adoption of "Strained-Silicon" - which whilst being
beneficial for future Ghz scaling, suffers high leakage.
Vis., leakage = high idle wattage = 40W doing nothing.
Agreed, the Prescott is a very hot chip - so much so that
boards should really be operated under stress in a chassis,
so the board itself can benefit from forced air cooling also.
As we move thro 2004 into BTX, and hotter CPU, hotter VRM,
hotter RAM (DDR2 1GB 667Mhz being very hot) so the board
components itself will require heatsinks, heatspreader etc.
Voltage-drop & die-shrink are underperforming frequency as
a rule, and so thermal output continues to rise - and will rise.
Already VRM specs are 103A (!) and that will rise further.
If you are buying a new motherboard or case, might be worth
biting your lip / chewing the sofa and holding off for BTX. AMD &
Intel will release boards for it - I'm not sure that case makers
will create a hybrid ATX/BTX compatible case as with AT/ATX.
BTX flips everything around quite radically to give a fix to the
heat problem - as well as obsoleting everything in sight
Intel's P-M is a good comparison of how Intel can get it right,
good performance with very low thermal output (22W). Seems
the old adage of 1/2 performance is possible for <1/5 the power.
Admittedly I/O isn't great - but for blades it could be made good.
So I wouldn't extrapolate too much on the Prescott, but I would
also wait for the socket changes & some clock ramping too. Could
well be the leakage on scaling down to a smaller die was too
much with the Northwood architecture, so Intel created Prescott.
Prescott's deeper pipeline comprehensively eats the cache doubling.
Chip area / Transistor count on Prescott is odd - could well be
64-bit extensions in there, or eventually in there. P4-EE is pricey.
AMD still have a good offering in the Opteron/Athlon64, with the
P4-SMP (Xeon) being really quite jurassic in comparison. Opteron
is the Xeon Intel should have released by now, Tajas is indeed a
good chip - but again heat output thus far is somewhat shocking.
It's also not just the heat output - but the leakage, where the
"sitting idle" CPU itself is kicking out a considerable load of heat.
A case of "Human Inside, Intel Outside" perhaps