A desktop replacement computer is a laptop that provides most of the capabilities of a desktop computer, with a similar level of performance. Desktop replacements are usually larger and heavier than standard laptops. They contain more powerful components and have a 15" or larger display. Because of their bulk, they are not as portable as other laptops and their operation time on batteries is typically shorter; instead, they are meant to be used as a more compact, easier to carry alternative to a desktop computer.
Some laptops in this class use a limited range of desktop components to provide better performance for the same price at the expense of battery life; in a few of those models, there is no battery at all and the laptop can only be used when plugged in. These are sometimes called desknotes, a portmanteauof the words "desktop" and "notebook," though the term can also be applied to desktop replacement computers in general
In the early 2000s, desktops were more powerful, easier to upgrade, and much cheaper in comparison with laptops. But in the last few years, the advantages have drastically changed or shrunk since the performance of laptops has markedly increased. In the second half of 2008, laptops have finally outsold desktops for the first time ever. In the U.S., the PC shipment declined 10 percent in the fourth quarter of 2008. In Asia, the worst PC shipment growth went up 1.8 percent over the same quarter the previous year since PC statistics research started.
The names "Media Center Laptops" and "Gaming Laptops" are also used to describe specialized members of this class of notebooks.
The basic components of laptops are similar in function to their desktop counterparts, but are miniaturized, adapted to mobile use, and designed for low power consumption. Because of the additional requirements, laptop components are usually of inferior performance compared to similarly priced desktop parts. Furthermore, the design bounds on power, size, and cooling of laptops limit the maximum performance of laptop parts compared to that of desktop components. The following list summarizes the differences and distinguishing features of laptop components in comparison to desktop personal computer parts: