To add my chip on the heap, I routinely get audio stuttering and/or desyncing after fifteen or thirty minutes with a cable card tuner (HDHomerun Prime), in one exact scenario: when I'm watching HD channels on a PC with a wireless connection. If I'm watching SD, it never happens, and if I'm watching HD on a wired connection it never happens. When the issue happens it never corrects, the audio stays goofed up and or desynced until I stop and restart playback.
I know that seems to suggest a bandwidth issue, but it's odd because up until that point playback seems to work fine (no stutter of video or audio), and I've monitored my wireless connection and there seems to be no changes in signal strength correlated with the hiccups. I also have fast wireless (connection is typically more than 100mbits down).
And even on a gigabit wired connection I do tend get isolated small hiccups (video and audio) every 15 or 30 minutes or so, but it usually clears quickly (within a few seconds), but it's a noticeable pause that recurs regularly. I'm guessing that whatever causes that hiccup in the wired context is causing more significant issues in the wireless context. A longer or configurable buffer might help.
It doesn't seem to matter whether the PC in question is using RO Standard or ROHQ.