If you've spent any time browsing our Computer Components collection, you've probably noticed just how many parts go into a single PC. Every build, whether it's a first-timer's starter rig or a full workstation, breaks down into the same handful of categories: CPU, graphics card, RAM, storage, motherboard, case, cooling, power supply, and the odd add-on card. This guide walks through what each one does, what to look for, and where to find current stock in each category.

Quick Reference: What Each Component Does

CPUs (Processors)

Your CPU handles everything your PC computes, from opening programs to running games in the background. Core and thread count decide how well it multitasks, while the socket decides which motherboards it will fit. Current Intel desktop chips use LGA1700 (12th-14th Gen Core) or the newer LGA1851 (Core Ultra Series 2), which are not cross-compatible with each other despite being a similar physical size; AMD's current mainstream socket is AM5. See Intel's own LGA1851 and LGA1700 socket compatibility notes for the full detail.

Browse current stock in our CPUs & Processors collection.

Graphics Cards

A dedicated graphics card takes the visual workload off your CPU, which matters most for gaming, video editing and 3D work. VRAM capacity and physical length (against your case's clearance) are the two specs to check before buying. Discrete gaming card stock moves quickly and is limited storewide at the time of writing, so it's worth checking back regularly or asking us about upcoming availability.

See what's currently available in our Graphics Cards collection.

RAM & Memory

RAM determines how many programs, browser tabs and background processes your system can juggle without slowing down. 16GB is a comfortable everyday minimum, with 32GB worth it for heavier multitasking. Your motherboard determines whether you need DDR4 or DDR5 RAM, since the two aren't interchangeable.

Browse options in our RAM & Memory collection.

SSDs & Storage

Storage is where your operating system, programs and files actually live. An NVMe M.2 SSD plugs directly into a slot on your motherboard and is significantly faster than a 2.5" SATA SSD, which connects via a cable instead. For most builds, 1TB is a sensible starting capacity, large enough for an OS, everyday programs and a reasonable games library without filling up immediately.

Before buying, check your motherboard has a free M.2 slot and confirm which PCIe generation it supports (PCIe 4.0 and 5.0 drives are both backward compatible with older PCIe slots, but only run at the older slot's speed).

Browse the full range in our Internal Storage collection.

Motherboards

Your motherboard is the hub every other component plugs into. It fixes your CPU socket, your supported RAM type, how many drives and add-on cards you can fit, and what size case you'll need. Our motherboard range is currently between restocks, so check back soon or get in touch if you need a specific chipset for an upcoming build.

Browse our Motherboards collection for updates.

PC Cases

Beyond looks, a case needs to fit your motherboard's form factor, have enough clearance for your graphics card's length, and support the cooling setup you've chosen. Full tower cases give you the most GPU and radiator room; smaller form factors trade some of that space for a more compact build.

Browse the full range in our PC Cases collection.

PC Cooling & Fans

Stock air cooling is fine for most builds, but higher core-count CPUs and overclocked systems benefit from an all-in-one (AIO) liquid cooler. Radiator size (240mm, 360mm, and so on) needs to match what your case supports, so check case compatibility before choosing a cooler.

Browse the range in our PC Cooling & Fans collection.

PC Power Supplies

Your power supply (PSU) needs enough wattage headroom for your CPU and GPU combined, plus the right connectors for your graphics card. Efficiency ratings (80 Plus Bronze, Gold, and so on) affect how much of that power gets wasted as heat. Our PSU range is currently between restocks, so check back soon for updated stock.

Browse our PC Power Supplies collection for updates.

PC Add-on Cards

Add-on cards plug into a spare PCIe slot on your motherboard to add capability it doesn't have built in, such as Wi-Fi, extra USB ports, or video capture for streaming. They're a handy way to extend an existing PC without a full rebuild. Our add-on card range is currently between restocks.

Browse our PC Add-on Cards collection for updates.

Putting a Full Build Together

The thread running through all nine categories is compatibility: CPU socket matches motherboard, your motherboard determines whether you need DDR4 or DDR5 RAM, case form factor matches motherboard size, and PSU wattage covers CPU and GPU combined. If you're building from scratch and want a walkthrough of the three components most builders choose first, our PC Building 101 guide to choosing CPU, GPU and RAM is a good next read.

Frequently Asked Questions

What computer components do I need to build a PC?
At minimum: a CPU, motherboard, RAM, storage, a power supply and a case. A graphics card is optional if your CPU has integrated graphics and you don't need gaming-level performance.

Which components should I upgrade first on an older PC?
RAM and storage upgrades tend to give the most noticeable everyday speed improvement for the cost. A graphics card upgrade matters most if gaming or video performance is the bottleneck.

Do all computer components have to be from the same brand?
No. CPUs, motherboards, RAM, cases and cooling are largely mix-and-match across brands, as long as the socket, chipset and form factor line up. The main brand-locked choice is CPU socket: Intel and AMD CPUs need their own respective motherboards.

How do I know if a component is compatible with my PC?
Check your motherboard's socket and chipset against any new CPU or RAM, and check your case's dimensions against any new graphics card or cooler. Manufacturer spec pages list these details for every part.

Ready to Start Your Build?

Whether you're upgrading one part or building from scratch, browse our full Computer Components collection to see everything in stock right now.