<div dir="ltr">On Sun, Jan 6, 2013 at 4:03 AM, Roger Heflin <span dir="ltr"><<a href="mailto:rogerheflin@gmail.com" target="_blank">rogerheflin@gmail.com</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Sat, Jan 5, 2013 at 10:22 AM, Raymond Wagner <<a href="mailto:raymond@wagnerrp.com">raymond@wagnerrp.com</a>> wrote:<br>
> On 1/5/2013 09:37, Roger Heflin wrote:<br>
>><br>
>> The baseline Atom board with a good power supply runs<br>
>> about 30-40W at idle<br>
><br>
><br>
> Thats awful! My 3.1GHz Ivy Bridge with a middling power supply only runs<br>
> about 25W idle.<br>
<br>
<br>
</div>It is a 3 year old machine measured at the outlet plug.<br>
<br>
What kind of meter are you using to measure that?<br>
<br>
My ivy bridge laptop runs 17W at idle with the screen off, and that is with<br>
a low power laptop cpu vs a high power desktop cpu and for the most part most<br>
of the desktop motherboards don't do that well on power savings at the<br>
mb level, where<br>
the laptop chips are setup for power savings.</blockquote><div><br></div><div style>Way Off Topic: </div><div style>17W at idle is incredibly high for a laptop.</div><div style><br></div><div style>Without knowing the specs of your laptop, my experience would lead me to expect an Ivy Bridge laptop to idle at ~5W with the screen off and the CPU at idle.</div>
<div style><br></div><div style>My 4+ year old Core 2 Duo can do 9 Watts with the screen on its lowest brightness setting (tested using a lab-grade Fluke), dropping to around 6.5W without the screen. Ivy Bridge can power gate whole cores and the GPU, so I would expect it to do substantially better.</div>
<div style><br></div><div style>I can imagine that under Linux there may be problems with some of the throttling features, and if your laptop includes a discrete GPU with a switching technology like Optimus it may be not operating correctly, leaving the dGPU powered constantly, but that reflects more on the OS than the hardware.</div>
<div style><br></div><div style>I remember seeing something (Phoronix maybe?) where a Macbook Pro tested under Ubuntu used about twice as much power as the same system running OS X - I wonder if something similar is at work here?</div>
<div style><br></div><div style>- Chris</div></div></div></div>