[mythtv-users] MythTV backend running on NVIDIA Ka-el, 35W replaced by

mythtv mythtv at beadon.ca
Wed Mar 9 01:28:26 UTC 2011


>> I'll go back to working on reducing the temp and power footprint of my
>> current system.
> 
> There's nothing wrong with striving or low power consumption.  There is 
> something wrong with taking it to an excess.  As mentioned, with average

> utility rates in North America, you're looking at 1W of sustained 
> consumption being roughly equivalent to $1/yr.  Once you understand 
> that, figure out how much you're willing to pay in power costs, and then

> you can start looking at what hardware you can purchase to fit under 
> that budget.
> 
...
> The other alternative is to simply not run the machine all the time.  
> MythTV has the capability of setting up timers to go into standby or 
> shutdown, and automatically come back online when requested by a 
> frontend, or needed for a recording.  Low duty cycle will beat out a low

> power system every time.
> 

> http://www.tomshardware.com/reviews/intel-e7200-g31,2039.html
> http://www.tomshardware.com/reviews/25w-performance-pc,2551.html

I have read those reviews and found them very interesting.  My backend
does double/triple duty as a fileserver/LAMP/VPN so it must be on 24/7 to
be useful.
The primary reason I want to reduce my power footprint right now is that
my combined BE/FE sits below my TV and the fan is noticeably loud.  My
current HTPC case is sadly limited in system fan options and my PSU fan
seems to ramp to 100% (loud) at 55C.

I've got a new case that has more ventilation and will allow >60mm fans
(why did I buy a case that only has 60mm fans?... just dumb).  I also have
a friend who's working on a 3 wire fan controller that would allow you to
customize fan speed ramp rate using a microcontroller.  For example
allowing <100% fan speed at 55C without resorting putting resistors in
series or other "analog" hacks.

FWIW my system is pulling ~85W from the wall with the following
components:
Intel Core 2 E6600
NVIDIA nForce 630i chipset
NVIDIA GT220 HDMI video
Hauppage HVR-2250
PCIe SATA controller (not enough SATA on mobo)
3x 2.5" HDD
3.5" HDD 
DVD drive
MCEUSB USB IR receiver
Antec earthwatts 80+ Bronze 380W

Viewing content vs idle doesn't make any noticeable difference in power. 
I'm a little more surprised that recording 4 shows simultaneously only adds
a few watts on top of the 85W baseline.

I started a couple years ago with a very similar setup running about 150W.
I dropped my underutilized analog PVR-500 tuner and that saved ~20W. 
After my RAID array had a failure I replaced a 3.5" drive with a 2.5" one
and noticed about 5W less power.  So I moved everything except my 1.5TB
drive to 2.5" disks as time and budget allowed.  That got me to 115W.  Then
I swapped my PSU from a non 80+ 400W to 80+ 360W and saw it drop to 85W. 
So for $50 (not incl the "necessary" cost of replacing old drives) I've
dropped to 57% of my original power usage.  :)

The i5 CPU certainly is interesting but at $350 for CPU, mobo, RAM it is
hard to justify.  I'm seriously thinking about experimenting with the
PicoPSU 130W as a way to further improve my power efficiency without a
large expense.

tinker tinker tinker...  :)


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