i was getting stuttering playback when playing multichannel DSF files. About every 30 seconds it would pause briefly. Just enough to be really annoying. Tried increasing the buffer, decreasing the buffer, playing from memory, not playing from memory. All to no avail.
I went to task manager to see what was going on. Simultaneously recording TV and listening to DSF multichannel brought CPU usage to 50% +-. But there was an app that was causing CPU usage to go to 100% periodically. Antimalware Service Executable. Turns out that app gets priority over uninterrupted music in a standard Windows 8 setup. And it is fixable. Just change the priority in Task Scheduler. And there's a video showing how to do it.
Here is the YouTube link. http://youtu.be/-NV45Mmn7TE
After the "fix", it takes a max of 1% of CPU usage, and DSF playback is smooth. Buffers back to normal, reading from memory or not, all is smooth and musical.
So, it was not a JRiver problem. Just thought I would share it.