I am re-posting this here for clarity (I am using MC21) and at Jim H's suggestion.
The issue is strange and has to do with the downsampling of DSD files that I do in order to have roomEQ from DiracLive (which works only in PCM up to 192k).
This is with files on a NAS connected to the same switch as the server, with files from a directly-connected USB drive and with files on an internal SSD:
1. With a DSD256 5 channel file converted to PCM and DiracLive, success depends on the target resolution:
a. Converted to 192k or 96k, loading is slow and there are interruptions and bufferings every 30 seconds or so. Dirac on/off makes no difference.
b. Converted to 176k or 88k, everything plays fine without interruption. Dirac on/off makes no difference.
2. In all cases, the CPU/memory usage seems similar (5-22%, mostly in the teens, and memory usage at 2-4 GB). However, when I look at the individual cores, only 4 are running and the others are “Parked.”
3. On the other hand, network behavior varies strangely. In case 1b (good playback), network usage averages 2% but peaks in the 85-100mb/s range. In case 1b (interrupted playback), the average is the same but the peaks are in the 50-60mb/s range. Changing from direct to play from memory changes the network activity pattern but not the peak values.
I do not know what all this means or what may be significant. I have a colleague with a very similar setup (i7, 16Gb RAM) who has the same observations. Sure, conversions to 88k and 176k are arithmetically simpler than to 96 and 192 but the limited core usage puzzles me.