[mythtv-users] VDPAU card power consumption

Ronald Frazier ron at ronfrazier.net
Fri Dec 4 14:31:43 UTC 2009

I'm considering making the switch to VDPAU sometime soon, as it would
be nice to be able to watch a bluray rip without spending an
additional 6 hours transcoding it first :) I just need to figure out
which card to go with.

I've got a good handle on a lot of the stuff, like the various
deinterlacing available on different cards (I suspect I'll be
satisfied with any of the cards) and the various levels of
acceleration (xvid/divx only accellerated on the newest cards, which
isn't a problem since everything now is coming in h264 and all my old
xvid/divx stuff works fine with CPU decoding). I guess the one aspect
on which I don't have very good info is on power consumption. Power
consumption is an important consideration in every upgrade I make
(especially here, since a high-power-demand graphics card could cost
more in electricity over a year than the card itself).

I've done some looking and found various charts on power consumption
from a variety of these cards, but I'm not sure how relevant they are.
First, a lot of the charts just list the GPU, not a specific card,
which makes me think that the figures they mention are just taken from
specs and not actual measurements (as we know the same GPU can be
different in different brand cards). Second, when they list power
consumption under full load, I'm not sure how relevant that is for
VDPAU playback. I'm not sure that VDPAU playback would stress all of
the circuitry that gets used in 3D rendering and stuff, so even if a
card uses 50 watts under full load, it could be possible that it only
uses 20 watts for VDPAU.

So, I guess I was wondering if anyone had any more concrete stats on
this for the various models. Perhaps someone that has a kill-a-watt.
I'm just wondering how big of an impact this will make on the total
system. In addition to different consumption of different model
GPU/card brand, I'm also considering that part of that demand will be
offset. For instance, if I disable the onboard video chip, I'm not
sure if that would shut the chip down and reduce the motherboards
power consumption. Also, if I recall correctly, there is something
like a 20-30 watt variance between CPU idle and CPU load on my system.
If VDPAU takes nearly all the load off the CPU, it's conceivable that
the power demand on some cards could be entirely offset by reduced CPU
power demand.

Thanks for whatever info anyone can provide. Also, are there any other
factors I may not have considered (power consumption or otherwise)?

More information about the mythtv-users mailing list