Amperage chart for motherboards/cpus?

Anyone know of a compiled database of amperage requirements
for motherboards and cpus? For some reason motherboard
manufacturers don't list this info in their specs, and cpu makers
give a wattage rating but not whether it's 3.3, 5 or 12v.

Thanks,
Rick

I have never seen a data base of motherboard power requirements.

Intel lists the current requirements and voltage requirements for all of its
CPU's, along with the maximum wattage. I assume AMD does the same.

No presently manufactured PC compatible CPU's use 3.3, 5, or 12 volts. The
design specifications for motherboards that use Pentium 4 class CPU's call
for a 12 volt supply to the on-board non-linear switching voltage
down-convertor/regulator that supplies ~ 1.5 volts to the CPU. Since this
is a switching convertor/regulator, relatively little power is wasted as
heat as would be if it were a linear voltage regulator. The conversion is
perhaps 80% efficient, so if the CPU requires 80 Watts (1.5 volts at ~ 53
Amperes), then the 12 volt requirement for that regulator will be about 100
Watts, or 12 volts at ~ 8.5 Amperes.

The power required by a motherboard itself is minor compared to the power
requirements for the CPU, memory, display adapter, and drives; all of which
are not choosen by the motherboard manufacturer. Only the chip set is a
significant power consuming component on the motherboard (other than the
down-convertor/regulators that supply on-motherboard-regulated power to the
CPU, memory, and display adapter.) If you have to have a number for the
power consumed by the motherboard itself, including the chip set, try 25
Watts. I don't know which supply line that would be from with newer boards,
but since switching voltage regulators are more efficient working from 12
volts rather than 5 volts the 12 volt supply may be the source. In
addition, the specifications for ATX power supplies for Pentium 4 CPU's (ATX
12V 2.03) require power sharing among the 12 volt, 5 volt, and 3.3 volt
lines, so the total, combined power rating for these three lines is the
important number, not the individual power ratings.

Phil Weldon, pweldon.DeleteThis@mindspring.com

"Rick" <me.DeleteThis@privacy.net> wrote in message
news:bhp8u7$1pk7q$1@ID-82690.news.uni-berlin.de...
 > Anyone know of a compiled database of amperage requirements
 > for motherboards and cpus? For some reason motherboard
 > manufacturers don't list this info in their specs, and cpu makers
 > give a wattage rating but not whether it's 3.3, 5 or 12v.
 >
 > Thanks,
 > Rick
 >
 ><!-- ~MESSAGE_AFTER~ -->