[mythtv-users] Low power FE/BE CPU

Johnny jarpublic at gmail.com
Fri Nov 13 18:11:38 UTC 2009

> AMD Sempron 140 Sargas 2.7GHz Socket AM3 45W Single-Core Processor
> -- unfortunately, I can't find a Socket AM3 MB with an nVidea GPU on
> it, so I don't think I'm interested in this one.  Perhaps one exists,
> and I just couldn't find it?

nVidia is exiting the integrated chipset business completely so I
think this will be standard going forward.

> Everything I've read about MythTV has said that I shouldn't have any
> problems at all running it with a modern dual core processor.  But
> these are all single core processors.  Since I want to offload as much
> of the HD decode to the nVidea CPU as I can, will this be an issue?
> What about commflagging and other CPU intensive tasks?

The dual core is generally recommended so that commflagging, database,
etc could be on one core and playback on another. But if you are using
hardware acceleration then you will probably be fine with a single
core. However this will depend on your usage scenario. If you are all
SD then you will be fine. On the other hand if you are regularly
recording and comm-flagging 4 HD shows at once then you would probably
be happier with a quad core. Several people have said they can
comm-flag an ATSC 1080i stream in almost real time with an Atom. So if
you are typically just going to want one show comm-flagged real time
then you will probably be fine with a single core.

> Or am I focusing too much on the 35/45W processors and should I just
> aim at a dual-core 65W processor and depend on a reduced clock rate to
> reduce the power?

AMD and Intel calculate their TDP number differently so it isn't a
good idea to compare them straight up. That number idicates the
maximum power that would need to be disappated. The measure from
different spots on in the chip etc. Also these don't necessarily
represent the real world power usage, although they do generally
correlate with higher or lower power usage. You certainly could
undervolt a 65W processor and get the same sort of heat & power
footprint as the cheaper parts, and then you have the extra headroom
if you find you need it.

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

These will all have a fan, and the stock fans generally aren't that
quiet. So if you are going to buy and after market fan, this really
won't matter which processor you get. There are plenty of
heatsinks/fans that are almost virtually silent, esp with fan control.

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