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Old 17th March 2013, 09:33   #18021  |  Link
G_M_C
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Join Date: Feb 2006
Posts: 1,076
Chipping in on the DXVA /power usage / performance discussion:
My PC has a Q9650 CPU and ive fitted an MSI PE HD7850, coming from a HD5770. The CPU runs on stock speeds. I also make use of an SSD and low-RPM / green data drives. I output via HDMI to my receiver, which has a Panasonic plasma connected to it.

I'v downclocked and downvolted the GPU. This way it uses less energy. Accoring to my measurements the power usage of the downclocked 7850 is about the same as my 5770 used. This is because the HD7xxx series has much more performance/watt, uses almost no power in idle mode and of course the downclocking/downvolting.

In my installation is LAV filters/madVR/MPC-HT.
I have LAV filters installed and use CPU decoding only, and have madVR use the GPU for itself. This has several advantages:

Firstly LAV in CPU mode is -to me at least- a 'set-and-forget' installation. It always works, decodes everything I have which also inclused high-bitdepth encodes. It is rock stable for me.

Secondly software decoding is efficient to such a degree that my (not to recent) CPU doesn't even flex. That means the CPU doesn't need to be full-on, and as a result uses less energy and doesn't run hot.

On top of that this means that madVR can use the GPU for itself.

The GPU swithes to the downclocked/downvolted '3d-speed profile', without having DXVA interfering as some of the above have seen happen.

And even when downclocked/downvolted, my GPU hasn't been over 63% usage (43 degrees c and 35% fanspeed = no noise). And that was when testing a 1080i50 BBC-HD capture and madVR deinterlacing plus smoothmotion, using jinc 3 + AR (chroma) jinc 4 + AR (image) resulting in a 1080p50. A configuration/situation not often used to be honest (smoothmotion has no advantage here imho). [added] In normal situations GPU usage is approx 30%-40%.

My conclusion is that using CPU decoding and a relatively recent GPU is a good option. You can control both through BIOS and other tools, set their speeds/powerusage to your needs individually. Imho this is the easiest '-works-without-having-to-think-about-it-even-my-girlfriend-can-do-it-' installation you can have.

Last edited by G_M_C; 17th March 2013 at 10:08.
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