Power
While desktops, laptops and tablets all have the same core components in terms of processor, memory and graphics capabilities, as you move further along the portability scale, these components become increasingly less powerful. Components inside a laptop case typically run more slowly than those in a full desktop machine, and there's no room to install extra graphics cards, sound cards or capture cards. Generally speaking, laptops are still significantly more powerful than tablets and almost up to the level of desktops in capabilities. If you need the most powerful computers possible -- for video editing, game development or larger screens, for example -- then desktops are probably the way to go, but high-end laptops are almost equally capable.