Difference between revisions of "Power saving"
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| + | = Hardware = | ||
| + | |||
| + | If designing a new MythBox, choose efficient hardware - low power CPUs, | ||
| + | efficient hard drives, and efficient power supplies. | ||
| + | |||
| + | == CPU == | ||
| + | Low power CPUs such as the AMD 5050e 45W series should have more than enough | ||
| + | power even for an HDTV frontend. (add other efficient CPUS here) | ||
| + | |||
| + | == Hard Drives == | ||
| + | |||
| + | [http://www.wdc.com/en/products/greenpower/ Western Digital Green Power] | ||
| + | drives and | ||
| + | [http://www.seagate.com/www/en-us/products/desktops/barracuda_hard_drives/barracuda_lp Seagate LP] drives use much less power than their predecessors, especially when idle (~2W vs ~8W when idle), | ||
| + | and should keep up fine with even demanding HDTV setups. | ||
| + | |||
| + | Consider an SSD for the root drive, so that the media drives can spin down | ||
| + | easily when not in use. SSDs use as little as 1/2 Watt when idle. | ||
| + | |||
| + | == Display adapters == | ||
| + | |||
| + | Use a display adapter without fan. Those with fan usually have higher power consumption than those without. Fans are noisy, too! | ||
| + | |||
| + | == Power Supply == | ||
| + | |||
| + | Choose an [http://www.80plus.org 80Plus] power supply which are much more | ||
| + | efficient, and often no more expensive. | ||
| + | |||
= Automatic powerdown/wakeup = | = Automatic powerdown/wakeup = | ||
See http://mythtv.org/docs/mythtv-HOWTO-11.html#ss11.5 | See http://mythtv.org/docs/mythtv-HOWTO-11.html#ss11.5 | ||
| − | = CPU = | + | = CPU Frequency Throttling = |
[[Powernowd]] can lower the clock frequency when the CPU is idle. | [[Powernowd]] can lower the clock frequency when the CPU is idle. | ||
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which makes it all easy and automatic. | which makes it all easy and automatic. | ||
| − | = Display = | + | = Display Power Management = |
| − | |||
| − | |||
[[DPMS]] will turn off your display when the PC has been idle for a while | [[DPMS]] will turn off your display when the PC has been idle for a while | ||
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/sbin/hdparm -S240 /dev/sda | /sbin/hdparm -S240 /dev/sda | ||
| + | |||
| + | = Animated Themes = | ||
| + | |||
| + | Animated themes can actually add a few watts to your frontend usage! Consider using a non-animated | ||
| + | theme, or modify your theme to remove animations. | ||
| + | |||
| + | = Preview Window = | ||
| + | |||
| + | The Preview window in the recorded show listing causes the CPU to do real work | ||
| + | to display it - on my box an extra 15W was used, almost 25% above true idle. | ||
| + | Worse, frontends are often left on this menu screen, so it's almost always | ||
| + | playing. | ||
| + | |||
| + | Ideally MythTV could time out a preview after a set time, but in the meantime | ||
| + | you can simply disable the live thumbnail preview to save power. | ||
Revision as of 15:39, 17 July 2009
Contents
Hardware
If designing a new MythBox, choose efficient hardware - low power CPUs, efficient hard drives, and efficient power supplies.
CPU
Low power CPUs such as the AMD 5050e 45W series should have more than enough power even for an HDTV frontend. (add other efficient CPUS here)
Hard Drives
Western Digital Green Power drives and Seagate LP drives use much less power than their predecessors, especially when idle (~2W vs ~8W when idle), and should keep up fine with even demanding HDTV setups.
Consider an SSD for the root drive, so that the media drives can spin down easily when not in use. SSDs use as little as 1/2 Watt when idle.
Display adapters
Use a display adapter without fan. Those with fan usually have higher power consumption than those without. Fans are noisy, too!
Power Supply
Choose an 80Plus power supply which are much more efficient, and often no more expensive.
Automatic powerdown/wakeup
See http://mythtv.org/docs/mythtv-HOWTO-11.html#ss11.5
CPU Frequency Throttling
Powernowd can lower the clock frequency when the CPU is idle.
Powernowd is more or less deprecated, more recent distributions have other cpu throttling mechanisms. On Fedora, for example, the cpufrequtils package contains similar tools. The kernel has an "ondemand" cpu governor which makes it all easy and automatic.
Display Power Management
DPMS will turn off your display when the PC has been idle for a while
Hard Drive Spin Down
Spinning down you harddrives not only will save power but save the life of your drives.
hdparm can be used to spin down internet IDE and SATA drives. First you must disable access times to the drives to keep them from waking up.
Edit your fstab adding noatime and nodiratime.
vi /etc/fstab
LABEL=d3 /tv/d3 xfs rw,noatime,nodiratime 0 0
Now, add hdparm statements to rc.local to set the default spindown time, i have used 20mins as a timeout:
vi /etc/rc.local /sbin/hdparm -S240 /dev/sda
Animated Themes
Animated themes can actually add a few watts to your frontend usage! Consider using a non-animated theme, or modify your theme to remove animations.
Preview Window
The Preview window in the recorded show listing causes the CPU to do real work to display it - on my box an extra 15W was used, almost 25% above true idle. Worse, frontends are often left on this menu screen, so it's almost always playing.
Ideally MythTV could time out a preview after a set time, but in the meantime you can simply disable the live thumbnail preview to save power.
