Kaby Lake i5 NUC Review 3/3: Fan, Power, Conlusions (NUC7i5BNK)
The Kaby Lake i7 was slightly disappointing when it came to the noise levels so my hopes were high when it came to the i5 model. With the BIOS set to the default settings the fan does spin up quite easily, even when doing basic tasks like web browsing. Under full stress the noise levels do increase to a relatively noisy levels, however, it’s not nearly as bad as the i7 model was. Simultaneous stress of the CPU and the GPU pushed the i7 model up to 44 dB, whereas the maximum I measured on the i5 was about 40 dB. I’d say it’s even not so much about the level of the noise, but it’s more the profile of the noise that makes it more annoying. I’d say my i5 laptop is equally loud, but the noise profile is much more pleasant.
That being said, setting the fan profile to “Quiet” did make the NUC almost completely silent for web browsing and basic tasks like that. However, under full stress the results are obviously the same as the fan just needs to spin up to a certain level to keep the CPU from overheating under stress.
The following measurements are taken using a cheapo UNI-T UT353 sound meter and the BIOS of the NUC was set to the default settings. I’m pretty sure that my completely unscientific approach is quite laughable for the people who actually do this kind of thing for living. I’m also pretty sure that the numbers produced are not comparable with numbers produced by someone else in their tests. I’ve measured from the front of the NUC with the microphone of the meter 50 cm away from the front panel. I’ll try to do so with my future NUCs so hopefully the numbers can be compared between my measurements.
|Power off (noise floor)||33.5 dB|
|Windows 10, idle on desktop||34.8 dB|
|Prime95 running stress test on all cores
(CPU temperature 86 degrees C)
|3DMark Time Spy Demo
(CPU temperature 86 C occasionally)
but occasional peaks at 39.6 dB
It’s worth noting that 39 decibels is really quite much more than 33 decibels even if the numbers do not seem so much different. When the power of a sound source is doubled the sound level increases by 3 dB.
I also took some power consumption measurements for the Kaby Lake i5 NUC.
|Windows 10, idle on desktop||13.6 W|
|Prime95 running stress test on all cores||48.1 W|
|3DMark Time Spy Demo||45.4 W|
|MPC-HC playing 10-bit 120Mbps HEVC at 4k||19.2W|
The power consumption figures explain why the i5 model did not get as loud as the i7 did. Whereas the i7 reached up to 60 watts at some points, the i5 model stayed below 50 watts at all times. The chassis and the cooling solution for the i5 and the i7 models are very similar, so dissipating that extra 10 watts of heat obviously requires higher RPM of the fan.
The Kaby Lake i5 NUC (NUC7i5BNK or NUC7i5BNH) is a capable mini PC. When compared to the previous generation the performance has improved, albeit not that much. However, I wrote last year that pretty much the only thing that I thought was missing from the Skylake i5 NUC was a HDMI port and the capability to HW decode 10-bit HEVC video. This NUC does all that and more: there’s limited HDMI-CEC control capabilities, USB 3.1 port, external GPU connectivity via Thunderbolt 3 port and more.
The fan is a bit noisier than I had hoped. At the moment that would be the only thing that is curbing my enthusiasm over this NUC. You can modify the behaviour of the fan in the BIOS and that does improve the situation a good bit. Of course, you could move the mainboard to a completely fanless Akasa case and be done with it. They don’t come cheap though…
Other than that, this NUC strikes a great balance between performance, price and power consumption. It would be a good desktop replacement for people who don’t have great performance demands. If you’re finding it hard to understand the level of performance you can expect, it’s maybe good to compare the NUC to a laptop. A good upper-midrange laptop with an i5 CPU will feature similar performance as this NUC.
This time the recommended setup has 8 gigabytes of DDR4-2133 RAM that is known to work well in this NUC and a 275-gigabyte Crucial SSD drive. If you would like to equip your NUC in a different way or you’d prefer the NUC7i5BNH model with the 2.5″ slot, have a look at our build-a-NUC tool: the NUC Guru that will give you sound recommendations on your NUC setup.