Fan is the most noisy element in a PC and gets louder with aging and clogging.
The Celeron Intel NUC incorporates a centrifugal CPU fan.
fitlet – not having a fan and using solid-state disk, is silent.
Size. fitlet is one third the volume of the Celeron NUC
fitlet: 10.8 x 8.3 x 2.4 cm (0.22 liter)
Celeron NUC: 11.6 x 11.2 x 5.1 cm (0.66 liter)
Performance. fitlet performance is 50% higher than Celeron NUC
Features. fitlet is dual-head with twice the USB ports and 1-4 LAN ports
Celeron NUC has 1x HDMI, fitlet – 2x HDMI
6 USB ports in fitlet (2x USB3), 3 USB ports in Celeron NUC (1x USB3)
Up to 4 GbE ports (Intel I211) in fitlet, 1 (Realtek 8111) in Celeron NUC
Half/full mini-PCIe/FACET card in fitlet, half-size only mini-PCIe in Celeron NUC