We use Intel NUC5i3MYBE fanless, albeit with a big custom headsink bolted onto a metal chassis. I've tested it with original fan/heatsink still attached but unpowered fan and it has no problems running a complex audio synthesizer rendering engine (quite more CPU load than just simple playback), total CPU load is about 7% (30% of one thread of one core, the rest is virtually unloaded). Even with the unit completely wrapped in foam the core doesn't get any hotter than 80°C as reported by a diagnosis tool. The fan is also really quiet, personally I found the "whining" noise of the onboard DC/DC converters of some units a bigger issue than the fan noise.