# No GPU Load using 4870 when watching movies



## EastCoasthandle (Dec 14, 2008)

Hello,

I wanted to find out if there is any real GPU load when watching videos using WMP.  For me, the screen does flicker when just before WMP shows the video.  GPU-Z reports that my video card does clock up to 750/900 but there is sparatic GPU load. It usually jumps to 5% then back to 0%.  This may happen once, twice or three times before the video ends.  While watching the video the video card remains at 750/900.  When the video ends it goes back to 2D clock rate.  

So I have to ask, is GPUz accurate regarding GPU load under this condition or is something else going on?  The reason why I ask is that there is GPU activity:
-screen flickers just before wmp shows the video
-GPUz reports 750/900 
so what is going on here and why?


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## Mussels (Dec 14, 2008)

maybe it clocks up when it detects the movie, but then the hardware acceleration doesnt work?

While i see lots of people say it DOES work for them, none have ever posted proof that it does in fact work on anything other than blu ray disks.


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## silkstone (Dec 14, 2008)

Mine flicks between 0-3% when watching a dvd, It also goes up to the 3d clock rate. I guess DVD's don't take that much processing power as CPU flicks between 0-4% when watching a dvd.


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## EastCoasthandle (Dec 14, 2008)

Mussels said:


> maybe it clocks up when it detects the movie, but then the hardware acceleration doesnt work?
> 
> While i see lots of people say it DOES work for them, none have ever posted proof that it does in fact work on anything other than blu ray disks.



I know UVD is working when watching a HD movie do to the very low CPU usage.  However, there is no GPU load using GPUz.  So I have to ask if GPUz is taking account for any UVD or other activity from the video card (if that applies)?


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## Mussels (Dec 14, 2008)

EastCoasthandle said:


> I know UVD is working when watching a HD movie do to the very low CPU usage.  However, there is no GPU load using GPUz.  So I have to ask if GPUz is taking account for any UVD or other activity from the video card (if that applies)?



hmm. do they have a dedicated chip for it? could be that GPU-Z is only reading hte 3D parts, and not the accelerator/decoder parts.


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## btarunr (Dec 14, 2008)

^Test your GPU load during video playback using that. Using DirectX Video Output (DirectDraw), VLC can take advantage of UVD/Purevideo (with that accelerated video output option checked). D3D or OpenGL are there as well.


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## Mussels (Dec 14, 2008)

hmmm thanks BTA. it looks like VLC has had a few updates since i last used it, theres even a new GUI!


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## EastCoasthandle (Dec 14, 2008)

Same results as before:
1. GPU and Memory clocks goes into 3d mode
2. Screen Flickers
3. Video Plays
4. CPU is roughly 1%+
5. GPUz shows GPU load goes from 0% up to around 5%, intermittently.

Watching live streaming results in a consistent 1%-6% GPU load though.


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## ghost101 (Dec 14, 2008)

I only get load when using powerdvd.

Also, has anyone else noticed that after installing catalyst 8.12 the bios clocks are being ignored? For some reason it is running stock 3d clocks 24/7 ?


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## daehxxiD (Dec 14, 2008)

To find out if UVD works, download AMDGPUClocktool v0.9.8; this shows if UVD is Busy or not. If UVD is working you should be able to watch a 1080p Trailer with basically 0% CPU usage (around 8% when running @ 800mhz with my Core 2 Duo T7500, due to AAC decoding). 
Alternatively use Media Player Classic Home Cinema and use its integrated H264/VC-1 Decoder, in order to check under "filters" if the UVD is working. For DXVA 2 you HAVE to use EVR (Enhanced Video Rendering) under Vista or VMR9/EVR under XP. I kind of don't think VLC does that, so I can't see DXVA2 happening any time soon. 

The reason why you are seeing GPU usage when playing back a Video is simple: EVR/VMR9 renders the Video to a 3D-Surface as default. The GPU "thinks" it is running a 3D-Game and thus bumps up the Clocks, obviously it also renders the video but it is a very trivial task to do, which is why usage is so low. I honestly don't know if GPU usage goes up when using UVD, I would think not (it's a separate logic inside the chip I think), but it certainly goes up when decoding MPEG 2, as deinterlacing is done in shaders. I believe ATI disabled WMV-Acceleration in default because it would not work under Vista; can't say for sure on XP... If you have a CPU load of lower than 10% while watching a 1080p vid you can be sure it is accelartiong your WMV (again, depends on how fast your CPU is clocked... at 4ghz it wouldn't take much more than 15-20% for a Cpu to decode a 1080p Trailer (@2.2ghz my CPU is only at 40-50% when decoding a motion-rich 1080p trailer)).

As you can see in the attached file I can render a 720p video problemlessly at 800mhz; it would also work in software but that would spike my CPU at 80-90% @800mhz, running it like this it goes no further than 10%; in fact stays around 6-8% most of the time.


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## rav3n (Dec 18, 2008)

here, with 1080/720p x264 mkv media:
VLC uses even more cpu than MP or MPC with core avc; UVD is always @ idle tough

i have a 4850 + catalyst 8.12


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## daehxxiD (Dec 19, 2008)

rav3n said:


> here, with 1080/720p x264 mkv media:
> VLC uses even more cpu than MP or MPC with core avc; UVD is always @ idle tough
> 
> i have a 4850 + catalyst 8.12




You can't use Core avc if you want to use the UVD; you have to enable the internal filters on Media Player Classic Home Cinema for DXVA support. Core AVC is a pure CPU codec; at least for now.


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## rav3n (Dec 19, 2008)

is this alright, for MPC on XP?





i think i've already tried it, but i have to confirm when arrive at home


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## silkstone (Dec 19, 2008)

Does this really make any difference? modern CPU'swill play any movie with minimal activity right?


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## Mussels (Dec 23, 2008)

silkstone said:


> Does this really make any difference? modern CPU'swill play any movie with minimal activity right?



*if* you get GPU acceleration, you get 0% CPU load.

Many people think they have GPU accleration because usage is 'low' but its just the codec being efficient.


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