Major brands and manufacturers

There is a multitude of laptop brands and manufacturers; several major brands, offering notebooks in various classes, are listed in the box to the right.

The major brands usually offer good service and support, including well-executed documentation and driver downloads that will remain available for many years after a particular laptop model is no longer produced. Capitalizing on service, support and brand image, laptops from major brands are more expensive than laptops by smaller brands and ODMs.

Some brands are specializing in a particular class of laptops, such as gaming laptops (Alienware), netbooks (EeePC) and laptops for children (OLPC).

Many brands, including the major ones, do not design and do not manufacture their laptops. Instead, a small number of Original Design Manufacturers (ODMs) design new models of laptops, and the brands choose the models to be included in their lineup. In 2006, 7 major ODMs manufactured 7 of every 10 laptops in the world, with the largest one (Quanta Computer) having 30% world market share.^[52] Therefore, there often are identical models available both from a major label and from a low-profile ODM in-house brand

Upgradeability

Upgradeability of laptops is very limited compared to desktops, which are thoroughly standardized. In general, hard drives and memory can be upgraded easily. Optical drives and internal expansion cards may be upgraded if they follow an industry standard, but all other internal components, including the CPU and graphics, are not intended to be upgradeable.

The reasons for limited upgradeability are both technical and economic. There is no industry-wide standard form factor for laptops; each major laptop manufacturer pursues its own proprietary design and construction, with the result that laptops are difficult to upgrade and have high repair costs. With few exceptions, laptop components can rarely be swapped between laptops of competing manufacturers, or even between laptops from the different product-lines of the same manufacturer.

Some upgrades can be performed by adding external devices, either USB or in expansion card format such a PC Card: sound cards, network adapters, hard and optical drives, and numerous other peripherals are available, but these upgrades usually impair the laptop's portability, because they add cables and boxes to the setup and often have to be disconnected and reconnected when the laptop is moved.

Ergonomics and health

Because of their small and flat keyboard and trackpad pointing devices, prolonged use of laptops can cause repetitive strain injury.^[46] Usage of separate, external ergonomic keyboards

and pointing devices is recommended to prevent injury when working for long periods of time; they can be connected to a laptop easily by USB or via a docking station. Some health standards require ergonomic keyboards at workplaces.

The integrated screen often causes users to hunch over for a better view, which can cause neck or spinal injuries. A larger and higher-quality external screen can be connected to almost any laptop to alleviate that and to provide additional "screen estate" for more productive work.

A study by State University of New York researchers found that heat generated from laptops can raise the temperature of the scrotum when balancing the computer on one's lap, potentially putting sperm count at risk. The small study, which included little more than two dozen men aged 21 to 35, found that the sitting position required to balance a laptop can raise scrotum temperature by as much as 2.1 °C (3.8 °F). Heat from the laptop itself can raise the temperature by another 0.7 °C (1.4 °F), bringing the potential total increase to 2.8 °C (5.2 °F). However, further research is needed to determine whether this directly affects sterility in men

Performance

While the performance of mainstream desktops and laptops is comparable, laptops are significantly more expensive than desktop PCs at the same performance level.^[44] The upper limits of performance of laptops are a little bit lower, and "bleeding-edge" features usually appear first in desktops and only then, as the underlying technology matures, are adapted to laptops.

However, for Internet browsing and typical office applications, where the computer spends the majority of its time waiting for the next user input, even netbook-class laptops are generally fast enough.^[45] Standard laptops are sufficiently powerful for high-resolution movie playback, 3D gaming and video editing and encoding. Number-crunching software (databases, math, engineering, financial, etc.) is the area where the laptops are at the biggest disadvantage.

Components

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 usually are 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. ^[28]

The following list summarizes the differences and distinguishing features of laptop components in comparison to desktop personal computer parts:

• Motherboard – laptop motherboards are highly make and model specific, and do not conform to a desktop form factor. Unlike a desktop board that usually has several slots for expansion cards (3 to 7 are common), a board for a small, highly integrated laptop may have no expansion slots at all, with all the functionality implemented on the motherboard itself; the only expansion possible in this case is via an external port such as USB or a card slot such as PCMCIA. Other boards may have one or more standard, such as ExpressCard, or proprietary expansion slots. Several other functions (storage controllers, networking, sound card and external ports) are implemented on the motherboard.^[29]

• Central processing unit (CPU) – Laptop CPUs have advanced power-saving features and produce less heat than desktop processors, but are not as powerful.^[30] There is a wide range of CPUs designed for laptops available from Intel (Pentium M, Celeron M, Intel Core and Core 2 Duo), AMD (Athlon, Turion 64, and Sempron), VIA Technologies, Transmeta and others. On the non-x86 architectures, Motorola and IBM produced the chips for the former PowerPC-based Apple laptops (iBook and PowerBook). Some laptops have removable CPUs, although support by the motherboard may be restricted to the specific models.^[31] In other laptops the CPU is soldered on the motherboard and is non-replaceable.

Rugged Laptop

A rugged (or ruggedized) laptop is designed to reliably operate in harsh usage conditions such as strong vibrations, extreme temperatures and wet or dusty environments. Rugged laptops are usually designed from scratch, rather than adapted from regular consumer laptop models. Rugged notebooks are bulkier, heavier, and much more expensive than regular laptops^[26], and thus are seldom seen in regular consumer use.

The design features found in rugged laptops include rubber sheeting under the keyboard keys, sealed port and connector covers, passive cooling, superbright displays easily readable in daylight, cases and frames made of magnesium alloys or have a magnesium alloy rollcage^[27] that are much stronger than plastic found in commercial laptops and solid-state storage devices or hard disc drives that are shock mounted to withstand constant vibrations. Rugged laptops are commonly used by public safety services (police, fire and medical emergency), military, utilities, field service technicians, construction, mining and oil drilling personnel. Rugged laptops are usually sold to organizations, rather than individuals, and are rarely marketed via retail channels.

Netbook

Netbooks are laptops that are light-weight, economical, energy-efficient and especially suited for wireless communication and Internet access^[18][19]. Hence the name netbook (as "the device excels in web-based computing performance")^[20] rather than notebook which pertains to size^[21].

Especially suited for web browsing and e-mailing, netbooks "rely heavily on the Internet for remote access to web-based applications"^[20] and are targeted increasingly at cloud computing users who rely on servers and require a less powerful client computer.^[22]. While the devices range in size from below 5 inches^[23] to over 12^[24], most are between 7 and 11 inches and weigh between 2 and 3 pounds^[20].

Netbooks have a wide range of light-weight operating systems including Linux and Windows XP^[20] rather than more resource-intensive operating systems like Windows Vista as they have less processing power than traditional laptops