I am experiencing drop-outs in the audio on my Windows PC. What is going on?
The most common cause of audio drop-outs in Windows is spikes in the DPC latency.
A DPC or 'Deferred procedure call' is a Windows mechanism which allows high-priority tasks to defer or delay lower priority tasks. Obviously the CPU cannot process all tasks at the same time, so the OS has to prioritize them. Each task is described as a DPC object and is added to the end of the 'queue' or processed depending on the priority of the task (low, medium or high).
If a device driver with higher priority 'hogs' the CPU for an extended period of time, we describe this as DPC latency spikes. To circumvent this we have added a 'DPC Safety Buffer' to the TCNear System Settings. By increasing this, you increase the low level buffer in the driver. If the the buffer is higher than the spike caused by the problematic device driver, then you will have drop-out free playback. However, if the spike is higher than the buffer, you will experience a drop-out.
Though the 'DPC Safety Buffer' allows us to deal with very high DPC latency spikes, some device drivers cause spikes that are simply too high, and those spikes the 'DPC Safety Buffer' may be unable to work around. In those cases you should either disable the problematic device in device manager, or contact the manufacturer for a driver update. It is important to note that in these cases, the drop-outs are not caused by the TCNear driver itself.