<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"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Even 500ma at 5v (2.5w) is significant to me - I'm trying to build the<br>
lowest power machine possible, and 7.5w for three tuners is almost as<br>
much as the whole rest of the system...<br>
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This all really seems like far too much ado about nothing. Unless you're talking about off-the-grid operation, electricity is cheap. For a piece of hardware running all day, every day, it typically comes out to around $1/W/yr.<br>
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(based on the US EPA's published national average)<div class="im"><br>
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<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Is a couple bucks really worth all the heartache you're putting into planning such a low power device?<br>
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So going from a (poorly-designed) Core 2 Duo or Core i system that averages an 80W draw and running it 24/7 for a year costs you ~$80. When you drop that to a (typical) Core 2 Duo or Core i system that averages a 40W draw and run it for 24/7 for a year, you've saved $40/yr. So, just by choosing to not buy an inappropriate system, you can ensure your MythTV box costs you at most about $40/yr in electricity.<br>
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So, say that your system actually takes 7.5W and you get a magical 0W tuner. That means you've saved $32.50/yr over a typical PC (a typical PC with lots of headroom for when you need it, BTW) by using your low-power solution.<br>
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Now, if instead, you take that 40W PC with lots of headroom and configure it to shut itself down when not in use and to wake up when required for recording or playback, it may draw about 40W when in use and 0W when not. If you assume you'll average about 4hrs/day, that will cost you $6.67/yr--saving you $33.33/yr (more than you save by going to this 7.5W system).<br>
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So, you may think, "Well, I could have the best of both worlds--take my 7.5W system and shut it down when not in use!" That's actually true, and a good idea, but notice that if you do, you're going from $7.50/yr to $1.88/yr, which means you're only saving $5.62/yr for this change. Still worthwhile because there's no real loss for turning off the system when not in use, but there's not a lot left to optimize in the setup/not a lot of savings to be had, here.<br>
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In other words, a) the best way to save power is to shut off the system when not in use and b) there's a point of diminishing returns on reducing power, and you likely have far bigger wastes of power around your house you could concentrate on fixing. <br>
</blockquote><div><br></div><div>Actually the best way to save power is not to have the system in the first place. These discussions crack me up when I actually take a minute to think about them.</div><div><br></div><div>
Honestly, if $30 worth of electricity over the course of a year is cutting into your food budget... don't use mythtv at all... it's a luxury and a hobby that can be quite expensive. Now, if part of the enjoyment of the hobby is trying to build a system with the lowest power requirements possible... mostly because of the challenge of it... thats a different story.</div>
<div><br></div><div>Of course we would all love a powerful mythtv system that ran on perpetual energy... but until then I will take my full powered flexible and long lived systems over a low powered, limited, and likely soon to be obsolete system any day; at least I have some hope of using new features. For example 0.26 brings HLS... impractical on a low powered backend. Who knows what 0.27 and 0.28 will bring.</div>
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