Monitor audio stutters when under CPU load, USB sound issue?

[panther309]

I've got a 27" apple cinema display connected to a PC via displayport/mini displayport adapter. When playing music (through the display) while doing CPU intensive tasks, the audio instantly stutters, cuts out, grumbles, etc. This suggest my PC is simply not powerful enough however that's not the case (specs below).


What i've determined.
1. This only happens when using the apple display for audio.
2. When speakers/headphones are plugged in to the motherboard, everything works great.
3. This happens with all audio applications. itunes, vlc, winamp, etc.
4. When doing everyday tasks, everything is great.

The display uses its built in USB cable for audio, right? I'm thinking it's gotta be some typ of driver issue for USB audio. However I've updated all drivers so I'm stumped there.

Specs:
Intel Core i5-2500K @ 4.6GHz (65-70* under load)
CORSAIR CWCH60 Hydro Series H60 High Performance Liquid CPU Cooler
GIGABYTE GA-Z68MA-D2H-B3
G.SKILL Ripjaws X Series 16GB (4 x 4GB) DDR3 1600
Kingston HyperX SH100S3B/120G 2.5" 120GB SATA III SSD
SAPPHIRE 100326L Radeon HD 6670 1GB 128-bit GDDR5
Apple 27" LED Cinema Display (via displayport)


Thanks for any help!

 

[oynaz]

I think Anandtech stumbled upon this issue during review. Try checking their review and see, I believe they solved it.

 

[panther309]

hmm, This is the review: http://www.anandtech.com/show/3946/apple-27inch-led-cinema-display-review/1

They didn't mention anything about it, but I read that the audio can either come from the USB connection OR the displayport.. interesting as I didn't notice an option in Win 7 to choose which method.

 

[panther309]

found it: http://www.anandtech.com/show/4832/the-apple-thunderbolt-display-review/10

this is almost identically what i'm experiencing. However I'm using the older 27" display (non thunderbolt).

 

[mfenn]

The cinema display is using its own built-in sound card and not your onboard sound (that's why it is USB). USB processing is very sensitive to other processes using CPU and will easily yield control to CPU-intensive processes. If it doesn't get enough CPU cycles to fill it's buffer, the audio cuts out like you're experiencing.

As an experiment, try changing the priority of your CPU-intensive task to "BelowNormal" and see if the stuttering continues.

 

[panther309]

The cinema display is using its own built-in sound card and not your onboard sound (that's why it is USB). USB processing is very sensitive to other processes using CPU and will easily yield control to CPU-intensive processes. If it doesn't get enough CPU cycles to fill it's buffer, the audio cuts out like you're experiencing.

As an experiment, try changing the priority of your CPU-intensive task to "BelowNormal" and see if the stuttering continues.

Mfenn, you rock. I've actually fixed the problem since posting this and pretty much lead to the same conclusion as you.

My fix, however, was to ensure the audio is transferred to the monitor by the DISPLAYPORT, instead of usb. This fixed it completely and now I have no pauses/stutters when my cpu is working hard.

thanks again

 

[Zap]

Mfenn, you rock.

That's why we keep him here, and let him out of his cage now and again.

 

[mfenn]

Mfenn, you rock. I've actually fixed the problem since posting this and pretty much lead to the same conclusion as you.

My fix, however, was to ensure the audio is transferred to the monitor by the DISPLAYPORT, instead of usb. This fixed it completely and now I have no pauses/stutters when my cpu is working hard.

thanks again

Glad you were able to fix it! Using DP is a nice solution because that behaves like the S/PDIF output on a normal sound card, no USB to get in the way.

That's why we keep him here, and let him out of his cage now and again.

LOL! I took Friday off you know.