Audio stuttering on VMware Workstation with multiple cores/cpus

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Hi All,

 

We are experiencing a problem with audio on our environment.  When running on VMware Workstation (we’ve tried on both Workstation 7.x and newly releaed 8 — hardware version 7), if our machine has multiple cores (or multiple cpus), several audio applications have serious problems with stuttering audio during playback.  When changing back to 1 CPU, 1 core the audio is fine.  Specifically, this happens with Goldwave audio editor and X-Lite/Eyebeam/Bria SIP softphones from Counterpath. Playing the audio with something like Windows Media player seems to work fine.  Running the apps on native hardware with dual/quad core is just fine — it’s when they are run in a VM that there is a problem.

 

Sticking with 1 CPU 1 core is not a good solution as it has the effect of slowing down the processing other applications on the machine by 30-40% relative to having dual core.  This is an environment used by 400+ users and the audio is an important part of the environment as it is used in sales demonstration process for our organization.

 

We are currently using 64bit Windows 7 Enterprise as host (8GB of RAM), and Windows Server 2008 R2 64-bit as the guest (6GB RAM allocated to guest VM).  This is on i7-quad core mobile processors and solid state drives with virtualization extensions turned on, so there is plenty of horsepower.

 

We have made the tweaks appropriate to Windows Server 2008 to provide for better quality audio (per http://www.win2008workstation.com/win2008/enable-sound-acceleration) in the Server OS.

 

We saw similar issues in our previous Windows Server 2003 32 bit environment with the default VMware audio driver.  We worked around this by forcing a Creative Soundbalster PCI 128 driver into the environment and the problem largely disappeared.  Unfortunately, in our 64 bit environment, there doesn’t seem to be any alternative drivers for audio — and no 64-bit drivers from creative for ES1371 or open source drivers for that environment either.

 

We’ve tried setting the device to be ‘SB16’ via sound.virtualdev=SB16 (per http://sanbarrow.com/vmx/vmx-sound.html), however, it didn’t seem that Workstation 7/8 pays attention to that as device was exact same in Device Manager.  We’ve tried various combinations of the other options listed (playing with sound.maxlength and sound.smallbaclksize) without success.  We’ve tried running the apps with single-processor affinity and real-time priority — no difference.

 

Ultimately, we’re thinking this is a VMware audio driver problem on multi-core/CPU and since there are no alternative audio drivers out there, we’re at a bit of a dead-end.  We’ve spent many hours searching forums and trying different things, but to no avail.

 

Anyone have any ideas?  We’re stuck and would like to use our lifeline and phone-a-friend here (preferably to the audio driver engineer on Workstation ).  Dirver alternatives in 64-bit?  VMX tweaks?  Application tweaks?

 

Thanks all for any ideas/assitance you can provide —

 

Brad

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