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Topic: DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer (Read 12382 times) previous topic - next topic
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DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer

My laptop has Windows 7 x64 beta installed on it. When I play music with foobar2000, I encounter glitches using DirectSound as the output Device. I have tried changing or updating sound driver but neither of them really helped. While it works fine with WASAPI(exclusive mode), I will not be able to hear any sound from other applications. This is a problem to me as I am not always looking at the computer screen while listening to music so that sometimes without hearing the sound I cannot realize something like being sent messages on msn. I would like to ask if there is right now any way to get foobar2000 support the WASAPI shared mode. Thanks.

DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer

Reply #1
This might sound like a strange question, but do you have an NVIDIA graphics card in your laptop? I was in exactly the same boat as you with occassional stuttering sound under Windows 7 (and Vista for that matter). Using the WASAPI output module solved my problem, but sound was still a problem in other DirectSound only audio applications.

I eventually discovered that the sound glitches were being caused NVIDIA's PowerMizer feature, which dynamically changes the graphics card clock speed to preserve battery life. If I disabled the video adapter from the Device Manager, the audio stutters went away (but I was left with no video acceleration).

So some suggestions to try:
1. Play some music using Foobar2000 with the DirectSound output module.
2. Download and run the DPC Latency Checker. If you see massive red spikes with it that coincide with audio glitches, it's most likely a driver problem (I was seeing spikes well over 60000 every 10-20 seconds)
3. Disable your video adapter from Device Manager (you don't have to reboot). Monitor the DPC latency and listen for any audio glitches.
4. If there are still audio glitches, you can try disabling your wireless network adapter too (on my laptop the wireless adapter causes small DPC latency spikes, but not enough to cause audio drop outs)

If you find disabling the video adapter works for you, there is a workaround that doesn't involve living without hardware acceleration. Basically you need to disable NVIDIA's PowerMizer feature, meaning you GPU will be running at a fixed clock speed. I used RivaTuner to do this (through some cryptic options and settings), but there's another program called NV GPU Pro which should do the same thing with a minimum of fuss.

DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer

Reply #2
Not as bad as yours ...




Quote
(I was seeing spikes well over 60000 every 10-20 seconds)



WOW! It really works, Thank you!! See the aftermath:





DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer

Reply #3
I'm glad it worked for you Hector  Your DPC graphs look just like the ones I had, both before and after. As you're probably aware disabling PowerMizer will reduce battery life, but it's a small price to pay for uninterrupted audio.

DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer

Reply #4
... As you're probably aware disabling PowerMizer will reduce battery life...

And increase GPU temperature.

DirectSound glitches, caused by DPC latency/NVIDIA's PowerMizer

Reply #5
Thank you fraganator, I have the same problem, and I fixed it thanks to you, I posted how I did it on my sound card forum.

@bb10: and might lower your nvidia laptop GPU's durability, too. Remember the nvidia laptop chip problem.