mirror of https://github.com/BOINC/boinc.git
96 lines
3.4 KiB
PHP
96 lines
3.4 KiB
PHP
<?php
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require_once("docutil.php");
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page_head("Heat and Energy considerations");
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echo "
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<h2>CPU heat</h2>
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<p>
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When BOINC applications are running on a computer,
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its CPU chip produces more heat than when it is idle.
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The computer's heat sinks and fans are normally able to
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dissipate this heat sufficiently.
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However, if the fans become clogged with dust,
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they may not be able to cool the CPU adequately,
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and this can lead to premature failure of the CPU or motherboard.
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<p>
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To deal with this problem, we recommend that you:
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<ul>
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<li> Clean your computer's fans and heat sinks periodically.
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<li> Install a utility that monitors CPU temperature,
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such as <a href=http://www.pcworld.com/downloads/file/fid,7309-order,1-page,1-c,alldownloads/description.html>Motherboard Monitor</a> or
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<a href=http://www.diefer.de/i8kfan/index.html>i8kfan</a>
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(for Dell laptops).
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<li> If needed,
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set your <a href=prefs.php>general preferences</a> to throttle CPU usage.
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</ul>
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<h2>The energy cost and environmental impact of running BOINC</h2>
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<p>
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A computer running BOINC uses more energy than an idle computer.
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The amount of additional energy depends on several factors:
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<ul>
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<li> How many additional hours per day you
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you leave your computer powered on to run BOINC.
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<li> The energy consumption of your computer.
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<li> Whether you use your computer's power-management features
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to turn off your monitor when idle.
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<li> Your marginal electricity cost.
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</ul>
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Using some typical values for energy usage and cost,
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here are estimates of the monthly costs:
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";
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list_start();
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list_heading_array(array(
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"Computer state<br>(24 hrs/day)",
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"Typical power usage",
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"Energy per month",
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"Cost per month<br><font size=-2>assuming USA average of 8 cents/kWh;
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<br>the cost in Europe is about 50% higher.</font>"
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));
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list_item_array(array("Off", "0 watts", "0 kWh", "$0"));
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list_item_array(array("Idle", "100 watts", "73 kWh", "$5.84"));
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list_item_array(array("Active", "150 watts", "110 kWh", "$8.80"));
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list_end();
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echo "
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Under these assumptions, running BOINC costs about $3/month
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more than leaving your computer on but idle,
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and about $8.80/month more than leaving it off all the time.
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<p>
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There may also be an environmental cost.
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If your electricity is produced by burning fossil fuels,
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the extra electricity usage produces greenhouse gases
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that contribute to global warming.
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If this is the case, we recommend that you
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not leave your computer on just to run BOINC,
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or that you reduce your overall energy use to compensate.
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<p>
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You can measure the power usage of their computer using
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a power consumption meter.
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These are available for
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<a href=http://www.energydudes.com/proddetail.php?prod=0001>American</a>
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<a href=http://www.pat-training.co.uk/230V_electricity_meter.htm>UK-type</a>
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electrical outlets.
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<h2>How reduce BOINC's energy usage and cost</h2>
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Some possibilities:
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<ul>
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<li>
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Set your <a href=prefs.php>general preferences</a> to allow BOINC
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to compute while your computer is in use,
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and turn your computer off when it's not in use.
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<li> Use your computer's power-management features to
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turn off your monitor when it's not in use,
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or to enter a low-power mode.
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A <a href=http://eetd.lbl.gov/EA/Reports/39466/>
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technical document about computer power management</a>
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is available from Lawrence Berkeley Laboratories.
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<li> If your electricity costs vary according to time of day,
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set your <a href=prefs.php>general preferences</a>
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so that BOINC computes only during periods of low electricity costs.
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</ul>
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";
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page_tail();
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?>
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