The Intel NUC proves just how small a desktop-class, 4K-capable Haswell PC can go. What the NUC doesnt do, though, is let us switch out the processor – it comes with either a Core i3 or i5 soldered to the mainboard. Now, Shuttles DS81 is slightly bigger than the NUC, but its still tiny (19 x 16.5 x 4.3cm) and its H81 chipset supports user-upgradeable processors up to a Haswell Core i7.