omg i registered here just to report a similar problem. Glad someone else has the same problem. Let me explain everything.
I installed windows 7 2 months ago and everything worked flawless till yesterday i installed packetix vpn and i my audio started distortions. Not knowing packetix was the problem i went thru the whole routine to get my problem fixed including running xperf to check the culprit for the latency problem. However i have come to the conclusion that latency by itself is not the cause of the audio distortions and i'll explain why. First in dpc checker i only get yellow bars every 15 seconds and i found out after a lot of testing, its because of my battery. The ACPI system checks for the battery health every 15 seconds and that causes a spike, so i removed my battery and guess what, the yellow spikes is gone. But wait i still have audio distortions...
Next in xperf my highest is Unknown ( which later became USBPORT.sys after i uninstalled Deamon Tools and removed SPTD.sys which obviously is not responsible for the stutters because i was using DT for a while without any problems) which is at 20,047 count and dxgkrnl.sys at 4388 count then ataport.sys at 1024 and Wdf01000.sys at 1172 count. Unknown/USBPORT.sys used to be in 40,000 count until i removed DT and SPTD.sys. The reason usb is the highest is because i use alfa wireless card with a usb 2.0 hub which is attached to my usb mouse.
After spending 24hours testing yesterday i believe the audio glitch is not because of dpc latencies whatsoever. I know this because i have removed all my drivers and resintalled them. Removed all usb devices and checked xperf and the 20k range usbport.sys does not show up but still audio distortions.
So now we have to move to another direction to find out why this is happening and im glad that someone here has found the culprit and its the audio/video enhancement option of packetix vpn. My problem started right after that.
Also in my attempt to fix this issue i installed srs audio sandbox and it improved the problem a lot but i still have distortions/cracks/static when im listening to music or watching a 720p movie. During music it happens occasionally when cpu spikes and during 720p movies audio is distorted the whole time and while you can still listen, it just ruins the experience. Normal xvid movies seem to be ok with occasional spikes if cpu boosts.
Even with the dpc latencies all pc operation is flawless for my system and im an IT professional so i know how to keep my laptop in tip top condition. Also the first thing i did when i started to fix the problem was to uninstall packetix and yet it hasnt fixed the problem. Now that we know packetix is the culprit i hope a solution is found.
It's always worth a try.
