At 04:52 PM 10/05/2006, Greg Sevart wrote:
CPUs dissipate their full consumed electical power as heat (at least, >95%
of it), so the two are effectively one in the same.
Modern motherboards derive all the CPU power from the +12v rail, but you
must figure them to be about 70-85% efficient, at best. Also, AMD rates
their processors high...the X2 4800+ doesn't pull 110W.
If you figure 90W draw* full load at 75% efficiency, you're pulling about
9.3A off the 12v rail.
* = 90W is probably a bit high.
Thanks Greg. So the purposes of picking a power supply, if I use the
thermal power as the real electrical draw, and assume 75% efficiency, I
should be plenty safe in calculating my 12V rail requirements?
Yes, I would say this is an accurate statement, at least as it relates to
the processor itself. You would also want to take video consumption into the
calculation, as PCIe cards can consume a significant amount over the
motherboard itself...
You also want to make sure you never go above about 90% of the rail's
capacity (another reason I hate dual rail setups)
Greg
