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

[Johan.van der Kolk]

On 03/09/2011 03:01 AM, Raymond Wagner wrote:
> On 3/8/2011 20:28, mythtv wrote:
>> 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.
> Can you just move this machine to another room?  I've got my combo fe/be
> in the basement under one of my TVs, and I just cut a hole in the floor
> in the corner behind the TV to snake audio, video, and USB up through.
>
>> Intel Core 2 E6600
>>
>> 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.
> That E6600 should be dropping multiplier, and dropping the voltage to
> match.  Unless you're using VDPAU for all your decoding and idling all
> the time anyway, there should be a noticeable difference between
> playback and idle.  Check /proc/cpuinfo when your system is idle, and
> see what it thinks your clock speed is.  It should be something well
> below the stock 2.4GHz.
>

I tested that, it hardly made a difference. CPU at 900MHz, all voltages at lowest possible. maybe 5W reduction, and noticeable performance impact. (same processor)

>> 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.
> A 2.5" hard drive may use less than half the power of a 3.5", however
> three 1TB 2.5" drives will consume more than one 3TB 3.5" drive.  Make
> sure you have your system set up to allow idle spindown.  An idling 3.5"
> hard drive will consume 4-6W each, but ones that are parked and spun
> down will be well under 1W.

my new BE will be:

ASUS P8H67-V (need three PCI slots for tuners) @ 125 Euro  (6.5W idle power)
Intel I5 2400 @ 165 Euro (~20W idle power, 50W full load, they will not 
reach 95W TDP)
4 G RAM @ 46 Euro

+ 6 samsung 2TB drives in raid 5 or 6 (another 20W idle or 50W active total)

+ an 80+ bronze PSU Antec Earthwatts 380 or 450. (more powerfull PSU's 
become inefficient under the low load, even the 80+ gold models

I needed a new BE, so cost was less of an issue. Energy efficient was a 
requirement though.

This system should be efficient, but have enough reserve to do a couple 
of commdetects and transcodes while recording two to three programs


Johan


>