How to fix 99% of Win 7 audio problems

Some time ago I stumbled over an article about DPC (Deferred Procedure Call) in Windows and the issue of latency problems regarding that process.

Problem:
In essence, DPC relates to a CPU tunnelig process in which all streaming media (audio/video playback/recording etc.) in Windows are subjected to. Transferring data to and from a soundcard requires the device driver to send a DPC request to the CPU. As Windows can't multitask by design, each CPU-Core has only one queue for all hardware. It's a first in first out principle and the timing and flow is subject to whatever is happening in all running tasks, processes and services regarding hardware at the time.

This process is the basic problem for all audio malfunctions, there might ofcourse be other issues but if DPC latency is low and stable the problem is certainly found in either audio software or hardware settings.

How to fix and maintain sound issues:
DPC latency can be monitored in real time with this magnificent tool from Thesycon Systemsoftware. Being German, they also write thorough procedures on how to use it so I'll leave it to them to explain the process of eliminating problems. A more in depth explaination of DPC is also found on the bottom of that link.

In addition to their information - It's important to note that services, scheduled tasks and startup processes also should be checked in addition to drivers while verifying DPC latency. Many 3rd party services (and sometimes Windows services like diagnostics and similar) do heavy communication with hardware. These should be disabled while monitoring DPC latency to see what effect they have on your computer. As for software, all kinds of Media Centers, iTunes, integrated security software etc. usually installs heavy background processes cluttering up the system and should be avoided.

By trial and error over years using Windows based studios and live performance software I've found that every problem, especially on Win 7, have shown up on the DPC latency checker, thus making them easy to eliminate by following the above examples using Thesycon's benchmark.

For all of you with audio problems out there I hope this helps - Good luck!

Regards,
Rainer

Alkotashi said:

Some time ago I stumbled over an article about DPC (Deferred Procedure Call) in Windows and the issue of latency problems regarding that process.

Hey Rainer, we've been on the DPC tool for a few months now, it's definitely helped quite a few.


Ap

I would guess that this will help a few out there. Good one.

Aphelion said:

Hey Rainer, we've been on the DPC tool for a few months now, it's definitely helped quite a few.

Oh.. well, I'm new here, usually few people know about this but that's great.

Alkotashi said:

Aphelion said:

Hey Rainer, we've been on the DPC tool for a few months now, it's definitely helped quite a few.

Oh.. well, I'm new here, usually few people know about this but that's great.

Yes, but you included a lot of good info that wasn't posted before so thanks!


I pasted this from a post I'd made a couple of weeks ago.

https://www.sevenforums.com/attachmen...dpclatency.jpg

Don't think it can get much better than this.

Ap