cpu usage when playing DVD

Goodguy · Post by **Goodguy** » Mon May 05, 2008 9:08 am

As I try to keep things silent one target is to keep CPU usage as low as possible.
When playing DVD I'd like the GPU to do most of the job, letting the CPU to be idle.
But I do not really succeed.

When playing DVD CPU usage is around 50%. GPU usage is around 7%.This is with hardware acceleration turned on.
If I switch of hardware acceleration CPU usage will go up to about 70% during DVD play.

Is that all hardware acceleration is? Lowering cpu usage with about 20% in my case?
I did expect more...

Any ideas or comments?

My setup:
P4 2,4GHz
2 Gb RAM
ATI radeon HD 2600 pro
PowerDVD 7.3

JazzJackRabbit · Post by **JazzJackRabbit** » Mon May 05, 2008 5:45 pm

The only comment I have is that something is wrong with your setup. I don't think my CPU usage ever exceeded 10-15% when playing DVD, even when I had P4 Celeron/P4C. If you have 50% CPU load when playing DVDs on 2.4GHz P4 something is wrong with your setup.

Maybe it's because of PowerDVD 7.3? Latest editions are crap. Try PowerDVD 4 or Media Player Classic (free).

Melluk · Post by **Melluk** » Tue May 06, 2008 3:05 am

This could possibly be a DMA / PIO mode problem with your dvd drive.
I think i remember something like this from long ago.

Goodguy · Post by **Goodguy** » Mon May 12, 2008 4:36 am

Thankyou so much for your suggestions! Indeed it was DMA/PIO mode behind this problem.
Now DVD playback takes 8-13% CPU load.

To see if DMA/PIO was the problem I tried to copy files from DVD to disk. CPU usage then went to 100% until copying was finished. Then I was sure.

To solve this in Windows XP open device mgr.
Open IDE ATA/ATAPI controllers.
Select channel where DVD is installed and properties.
Select tab Advanced Settings.
Check that Transfer mode is 'DMA if available' and Current Transfer Mode is DMA mode.
For me it was PIO mode.
I tried to set transfer mode 'DMA if available' and restart computer, but PIO mode was used anyway.
I had to uninstall the secondary channel where my DVD is installed and restart.
The channel was then reinstalled by Windows and correct DMA mode was set by Windows.