Small and blazing fast. However, noise can be heard even when the load is not that heavy.=============Some advice on wireless keyboard and mouse=============If you use bluetooth or 2.4GHz USB receiver with wireless keyboard or mouse, you may probably encounter "lag" issue when typing or moving mouse. For 2.4 GHz USB receiver, try connect the receiver to a USB 2.0 extend cable (1 meter or longer) then to the NUC. For bluetooth devices, keep the device away from USB 3.0 devices, such as USB 3.0 HDD or flash drive.