On Mon, Jul 30, 2012 at 2:16 AM, Nikos Chantziaras <[email protected]> wrote: > On 30/07/12 07:28, Michael Mol wrote: >> >> On Sun, Jul 29, 2012 at 11:55 PM, Nikos Chantziaras <[email protected]> >> wrote: >>> >>> On 30/07/12 06:08, Michael Mol wrote: >>>> >>>> >>>> On Sun, Jul 29, 2012 at 10:50 PM, Nikos Chantziaras <[email protected]> >>>> wrote: >>>>> >>>>> >>>>> On 30/07/12 05:23, Philip Webb wrote: >>>>>> >>>>>> >>>>>> i5-2550K & FX-4100 both use 95 W >>>>>> (some of the more costly AMDs use 125 W ). >>>>> >>>>> >>>>> >>>>> >>>>> Note that power savings are not important if you're not using a laptop. >>>>> CPU >>>>> power savings on a desktop don't translate to any relevant amount of >>>>> money >>>>> on your electricity bills. This is because neither of those CPUs >>>>> really >>>>> use >>>>> 95W. That's just the thermal upper limit. >>>> >>>> >>>> >>>> To be fair, power savings are relevant if you're concerned about your >>>> electric bill, or if you're concerned about heat management in your >>>> system. >>>> >>>> Consider my dual E5345...leaving that on 24x7 appears to cost me about >>>> 90USD/mo. >>> >>> >>> >>> CPU power savings will transform that into a 89.9USD/mo ;-) That's what >>> I >>> mean. It's not worth much. It helps quite a bit with laptop battery >>> life. >>> But for desktops, it doesn't do anything too useful. >> >> >> If you really want the hard numbers, check out some place like Tom's >> Hardware or Phoronix. I forget which does the power consumption >> measurements. At some of the hardware review blogs, you can get >> numbers on idle vs full-load power consumption, as measured at the >> wall. The difference truly is striking. > > > When you have full load, the CPU won't clock down. So nothing saved there.
When you're considering full load, the TDP becomes a useful estimation of relative power consumption between different processors. > If you don't have full load, the clock-down doesn't save much compared to > max clocks while idle. This is where you're wrong. http://www.tomshardware.com/reviews/ivy-bridge-benchmark-core-i7-3770k,3181-23.html http://www.tomshardware.com/reviews/fx-power-consumption-efficiency,3060-11.html -- :wq
