High GPU usage on menus (1 Viewer)

[doveman]

MediaPortal Version: v1.2B
MediaPortal Skin: StreamedMP
Windows Version: Win7 Ult 64
CPU Type: Athlon II X4 630
HDD: 2TB Samsung F4
Memory: 4GB DDR2 1066Mhz
Motherboard: Biostar TA790GXB3
Video Card: HD6950 2GB
Video Card Driver: 11.5a
Sound Card: onboard Realtek AC97 (ALC662)
Sound Card AC3: no AC3
Sound Card Driver: 6.01.6299
1. TV Card: Hauppauge Nova-T 500
1. TV Card Type: DVB-T
1. TV Card Driver: 4.3.27240
MPEG2 Video Codec: Cyberlink PDVD11
MPEG2 Audio Codec: ffdshow
h.264 Video Codec: ffdshowDXVA
HTPC Case: Custom
Cooling: Scythe 120mm Bottom Intake Fan, Stock CPU HSF
Power Supply: OCZ StealthStream 400W
Remote: Nova-T 500
TV: Sony XBR800 36"
TV - HTPC Connection: DVI

I don't know if this is a bug or not, which is why I'm posting here, but I've found that in MediaPortal, just sitting on the menus and using MSI Afterburner's OSD I see that GPU usage constantly fluctuates between 0-8-18-44% (which seems ridiculous for just displaying a menu). The clocks are also constantly changing between low and high power modes.

If possible, I'd like MP to not load my GPU so much and to stabilise the clocks in low power mode, to save energy.

This is a screenshot from GPU-Z showing what happens when just sitting on the Home page:

 

[doveman]

I've done some further testing and found that this only happens in single display mode. When I run both my displays in Duplicate mode, this causes the clocks to stabilise at 450/1250 and the GPU load remains at 0%. VDDC Current is higher at 9A vs 5A however.

So it seems it's the clocks constantly changing in single display mode that causes the GPU load. The screenshots below were both taken over roughly 10 minutes.

Single display:


Duplicate displays:

 

[mbuzina]

Ehhm, so you are complaining the wrong way around

The first screenshot shows that the GPU saves power because the temp is lower and the clock is lower. It is a perfect example of saving power by going to lower power mode when possible. MP is drawn like a DX game, so on each image display (v-sync) the display is drawn again (by the GPU). The current is lower, partly the voltage is lower, so that is good.

The second screenshot shows that your driver is not able to save power when running 2 displays. That is to be expected, since the GPU has to do more work.

So what is your problem? If you want the GPU to save more power, use a less demanding skin (StreamedMP is one of the most demanding, use Default/Blue3 to save power).

 

[doveman]

Yeah, I realise that in single display mode the VDDC current is lower than in Dual display mode and I probably didn't present my question very clearly.

You say that the GPU has to do more work in dual display mode, yet it stays at 0% almost all the time, whereas in single display mode it's all over the place, up to 44%, and I also don't get why the clocks are going up and down all the time. It seems that MP is causing the card to keep switching between 2D and 3D state, which doesn't seem right. I'm not sure if the card has a low-power 3D mode plus a full-power 3D mode (as well as the 2D mode). In dual-display mode the core clock is pretty much fixed at 450Mhz, whereas in single display mode it jumps from 250Mhz right up to 800Mhz at times, which also doesn't seem right.

EDIT: Actually, I have to correct the above. The Core clock only changes between 250 and 500Mhz. The Memory clock switches between 150-300-625-1250Mhz (not necessarily in that order).

 

[mbuzina]

The gpu seems to be able to lower powernconsumption when running on one display only. So the first version probably uses less energy. Using 50% of a low power Gpu is probably less consuming than using a few % of a gpu running on full power.

If you want to have a comparison switch to a simpler skin. As mp uses directX display just like a game does, it draws constantly even on a "static" display. Since a media center usually should not be static in its display this is angood assumption.

 

[doveman]

Yes you're right that this card (and other ATI and Nvidia cards I believe) have a problem when running in multi-display mode, even at idle/2D, that causes the clocks to run at semi-3D speeds but they should stay steady.

However, with the help of someone over at the AMD forums, I've found that there's two things that cause these constant clock speed changes and high GPU spikes with MP. One is having Morphological Filtering enabled (which I need disabled anyway, as it messes up MP's fonts) and the other is running MSI Afterburner's OSD feature, which ironically was the thing that alerted me to the problem in the first place!

With those two disabled, the clocks stay steady and whilst there are still GPU spikes, which don't happen when running in dual-screen mode, they stay below 10%, compared to the up to 44% I was getting before.

Here's a screenshot, showing Afterburner's OSD off, then on, then off again: