Energy budget calculations for new system

[b3nbranch]

Hi,

I've been lurking in SPCR for several months, much to my benefit,
and now I'm to the point where I'm checking alternatives for a possible
new system. I'd like to draw up an energy budget for each alternative,
because this can affect choice of PSU, # of fans, etc. It's not too hard
to find watts measurements for CPUs (TDP) and graphics cards, but
I'm at a bit of a loss for reasonable figures for RAM and especially for
modern motherboards. Any suggestions or pointers? (This will not
be a heavy gaming system, but more of an Internet access and
C++ programming system).

I've got a kill-a-watt measuring the wall draw of my 3.5-year-old system
(see sig ), which idles at 135W and with cpuburn and graphics
both running pulls 166W. With up-to-date components I figure I should
be able to take a chunk out of that.


Thanks in advance!

[darthan]

Well, as far as mobos and RAM goes, call it 30-40W total max power and you'll be covered. RAM usually draws just 2-3W per stick and a mobo probably no more than 20W but it could be 30W so just use 40W as your guideline. You really don't have to worry about their power draw too much, it's pretty minimal (especially RAM). If you are running your PSU so close to its capacity that an increase of 10-20W will push it over the edge then you need a new PSU, not a different motherboard.

[Devonavar]

That's because other components aren't really that relevant for power consumption. CPU and GPU consume the lion's share of the power in all but the lowest end systems. MB power consumption is relevant when considering average power consumption, but it doesn't mean much when sizing a PSU, since it's maximum power consumption that matters.

I suggest looking at this article for info on RAM power consumption (or lack thereof).

Also, unless your system is really extrodinary, a 300W power supply is enough for just about anything. Check out this thread for proof...