EMZETT.Desktop PCs
In short: Stationary computers with a separate case, monitor, keyboard and mouse — unlike laptops, not intended for mobile use.
In more detail: Desktop PCs are usually easier to upgrade and repair than laptops, since components like RAM, graphics card or power supply are individually replaceable. In exchange, they lack mobility — they stay at a fixed workstation.
In Depth
Modularity as a central advantage
The central advantage of a desktop PC lies in its modular design: since every component (CPU, graphics card, RAM, SSDs/HDDs, power supply) is connected to the motherboard via standardised connectors and form factors, practically every part can be individually replaced or upgraded, without replacing the rest of the system. With laptops, by contrast, many components (especially the CPU and often also RAM) are permanently soldered, which severely limits repairs and upgrades, but enables considerably more compact and lighter cases.
Cooling and power draw
A desktop PC also has structural advantages in cooling and power draw: the larger case volume allows more efficient, quieter heatsinks and fans as well as a more generous power supply, while laptop components are often deliberately optimised for lower power consumption and less waste heat (and, in exchange, often run noticeably slower than their desktop counterpart with the same model name, since they have to throttle their performance more to avoid overheating in the tight case). These physical limits are the main reason why demanding applications like games with high graphics settings, or computationally intensive software, usually run noticeably better on a comparably priced desktop PC than on a laptop.
Form factors
Desktop PCs themselves come in different case sizes (form factors) — from compact mini-ITX systems through the common mid-tower to the spacious full-tower. Larger cases offer more room for cooling, more expansion slots for expansion cards and easier access for maintenance work, while smaller cases need less desk space. The choice of form factor, in turn, determines which motherboard size (e.g. ATX, Micro-ATX, Mini-ITX) fits at all.
Price-to-performance ratio
Since desktop components don’t have to be optimised for extreme miniaturisation, manufacturing per unit of performance is usually cheaper than with comparable laptop hardware — a desktop PC typically offers noticeably more computing power for the same price than a laptop, but has to accept the lack of mobility in return.
Pre-built vs. self-assembled
Desktop PCs can be bought fully configured (from large manufacturers or system builders) as well as completely assembled from individual components — a common path among experienced users to specifically optimise price-to-performance, or to achieve very specific component combinations that aren’t available pre-configured. Building your own requires basic knowledge of compatibility (socket, form factor, power supply) and some manual skill, but is made much easier by extensive community guides and compatibility-checking tools.
Configurability as investment protection
Since individual components age independently of each other (a graphics card typically becomes “too slow” for current games faster than a power supply or case becomes technically outdated), a desktop PC can be gradually upgraded over the years, instead of having to replace the entire system at once — an economic advantage over laptops, where usually only the complete device can be swapped once a single component (often graphics performance) is no longer sufficient.
See also: Laptops, Components, Motherboard/Mainboard