I run the HDMI output of the Qnap (451+, 8 gig RAM) into an Emotiva UMC-200. I am getting frequent dropouts for buffering when playing multichannel music files. It happens most severely with multichannel SACD ISO's where MC extracts a 1 bit, 352.8 kHz stream from the ISO but then has to convert it to 1 bit 192 kHz for use in my Pre Pro. Performance is similar if I convert to DSF as well. The dropouts happen less with 24/96 5.1 flacs, although a couple of dropouts per track is still unacceptable. It happens very rarely, if at all with stereo playback of any bitrate. When these dropouts happen the server display flashes to say its buffering. I increased pre buffering to the max, enabled read from memory, maxed out live playback latency and limited output to 192kHz. Some or all of these changes helped some, but the dropouts are still fairly significant. Any suggestions on how can I eliminate this problem completely?
I'm becoming more and more convinced that these single box server/NAS QNAP units do not have the processor horsepower to process High Resolution multichannel audio files. If you are thinking of using this for anything more demanding than 24/48 multichannel flac, I think you're going to be disappointed.
Upon further review: I have found that the real problem may be this particular implementation of MC. Kodi, which is also bundled with the QNAP servers, does not exhibit these problems. No buffering problems with 24/96 multichannel flac. No problems with multichannel DSF playback (Kodi does not support SACD ISO). While doing some resource monitoring while MC is playing, I get huge 90%+ usages on all four processor cores while playing back multichannel SACD ISO.