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Roon Headless on a NAS with the microRendu: An Important Follow-up

01-09-2017 | By Tom Gibbs | Issue 89

The NAS element of my Roon/QNAP/microRendu setup is a QNAP TS-251, which has the requisite 64-bit processor and sufficiently upgradeable RAM to run Roon Core effectively. And at a significant cost savings when compared to Roon's recommended QNAP setup ($500 vs. nearly $2000 USD). During my initial explorations of Roon late last year, I quickly discovered that my CPU usage was pretty excessive, and it only took a bit of investigation to discover the culprit.

Roon Headless

Roon has a couple of settings for Audio Analysis Speed that run constantly in the background, and they push your CPU usage upwards of 80 percent or higher consistently. Since these settings deal mainly with volume leveling, crossfade, volume normalization and waveform displays—all aspects of performance that are probably completely inconsequential to most audiophiles—I turned them off in the settings panel. The result of that action in no way reduces my enjoyment of Roon's core functions, but it does offer a substantial performance boost to my modest setup by dropping the CPU usage to an average of 2 percent. This is truly significant to my situation, and allows me to enjoy virtually everything Roon has to offer—and well within my limited budget. And with Roon running, the CPU usage on the NAS typically clocks in at around 5 percent, with occasional peaks of 10 percent or so, which leaves plenty of room for your processor to work efficiently without interfering with music playback. In terms of the overall experience: I'm completely ecstatic!

However, always being the constant tinkerer, I played around with the settings on the QNAP NAS control panel, setting the Firmware Update to automatic, and also joining the Beta program. The current official Firmware version for QNAP NAS units is 4.2.2 1216; as of a couple of days ago, a new Beta Firmware version 4.3.2 became available. Of course, I allowed the update to take place, and it arrived with a beautiful new interface with a substantially more active GUI. Smitten by the enhanced appearance and obviously upgraded functionality of the new update, I initially ignored the CPU usage monitor, which soon began displaying activity hitting regular peaks of 100 percent. 100 percent! And this is with no other processes (especially not Roon) active—there had to be some setting in the new control suite I had missed. I couldn't even begin to imagine how Roon playback would be affected by average CPU peaks of 70-plus percent.

So for about the last 24 hours I've been researching every aspect of the new firmware update, with no success—the process monitor shows that CPU usage is being generated by kernel-related functions running at averages of 70 percent with frequent peaks of 90-to-100 percent. It's so very new that very little information is available on QNAP's forums, or elsewhere on the web, for that matter. I can't help but believe that this is just an aberration in the new firmware, but you can never tell, and especially not this early in the game. So at this point, I've chosen to roll back the firmware to the previous version. Of course when you attempt that, you get a really disturbing warning screen, warning you that your unit may no longer function properly with a firmware rollback. But with some intensive exploration, I found enough testimonials that no ill effects were experienced by any users thus far, and I took the plunge. Within thirty minutes or so, my CPU usage had returned to much, much more reasonable levels—I can't begin to express my relief!


If you have any thoughts of pursuing the whole Roon-on-a-NAS/microRendu experience, and, like me, have limited resources—I'd very strongly recommend avoiding the QNAP Firmware update route until there's at least more verifiable documentation available regarding the gargantuan increase in CPU usage. Maybe it's something that QNAP just hasn't quite worked out yet, and maybe there hasn't been any significant outcry from users yet. And maybe, if you're running one of the high-end models, it's sufficiently juiced enough to manage without skipping a beat. However, if, like me, you're trying to get really great sound on a budget, like I said above, avoide at all costs  the QNAP firmware update. The whole idea behind getting the microRendu into the picture is to minimize the computer's footprint, and I can't see how the increased complexity of the new QNAP operating system will help achieve that. More to come!