[mythtv-users] Low power FE/BE CPU

[Jim Stichnoth]

On Fri, Nov 13, 2009 at 9:45 AM, Patrick Doyle <wpdster at gmail.com> wrote:
> If you're starting to recognize my name and/or email address, you'll
> see that I'm in the throes of analysis paralysis in building a
> combined FE/BE unit to replace my Series 2 TiVo.

I looked up your previous posts and I see that you are planning to use
a single ATSC tuner.  That means that (at least for now) you would
probably run only one commflag job at a time.  Some time ago, I ran
tests on a single-core 1.6GHz Atom (the Zotac IONITX-C board) and
found that ATSC commflag jobs could almost be done in real time -- a
60-minute program takes 75 minutes to complete commflagging.  That
sets a lower bound for performance.  Any of the other processors you
mentioned should perform substantially better.

> Today, I have decided to try to figure out what sort of CPU to put in
> there, and I've decided to focus on the minimum power consumption for
> the CPU.

My current master backend is a 65W Core 2 Duo processor on a
motherboard with integrated nVidia 9400 graphics.  I used to use it as
a diskless frontend.  At idle, the entire system drew 35W.  As a
master backend, I allow it to run 3 simultaneous jobs, and it keeps up
just fine.  You could use this as a reference point in your
calculations.

> I am interested in the lower power CPUs for both energy and noise conservation

It's hard to beat the ION system there.  My diskless ION frontends are
completely silent and draw about 17W at idle.  I have successfully
used it as a backend as well.  When I was preparing for a 0.22
upgrade, I repurposed one of these as a combined FE/BE for testing,
and it was totally adequate for the job.  Again, this gives a lower
bound on performance, so from a purely performance point of view, I
don't think you need to worry about the CPU.  Of course, this all
assumes you plan to use VDPAU.

Jim