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Your first PC build: every part, and what to check

Updated October 30, 2026

A desktop PC is eight parts that plug together. Four things must match; the rest is choosing how fast you want it to be.

The eight parts

  1. Processor (CPU). Runs everything; its socket decides the motherboard.
  2. Motherboard. Connects every part; must match the CPU socket and the memory type.
  3. Memory (RAM). Short-term working space; DDR4 or DDR5, as the board takes.
  4. Graphics card. Draws games and speeds up video and AI work; the biggest power draw.
  5. Storage (SSD). Holds Windows, games and files; an NVMe drive plugs straight into the board.
  6. Power supply. Powers every part; needs headroom above what the parts draw.
  7. Case. Holds it all; must fit the board size and the graphics card’s length.
  8. CPU cooler. Keeps the processor cool; some processors come with one.

The four things that must match

  1. Socket. The processor and the motherboard must share a socket: AM5 or AM4 for AMD, LGA1700 or LGA1851 for Intel. A newer processor on a board from the socket’s first year may need a BIOS update first.
  2. Memory type. The board takes DDR4 or DDR5, never both. Buy two matching sticks of the type it lists.
  3. Size. An ATX case holds ATX, Micro-ATX and Mini-ITX boards; a Micro-ATX case holds Micro-ATX and Mini-ITX; a Mini-ITX case only Mini-ITX. The graphics card’s length must be under the case’s clearance, both in millimetres in the listings.
  4. Power. Add up the processor’s and graphics card’s power and about 100 W for everything else, then choose a supply with roughly 40% to spare: graphics cards spike above their rating.

Buying parts used

  • Read the condition and the description: “tested and working”, “for parts” and “untested” mean very different things.
  • Check the seller’s return policy and feedback before you buy, and test each part as soon as it arrives, inside the return window.
  • Match the exact model: a listing for a newer or older model can look nearly the same. KeepHawk marks a listing that names a different model.
  • For a graphics card, look for photos of the card itself and ask whether it was used for mining.
  • For a power supply, buying new is often worth it: it protects every other part.

Plan your build Pick each part, see whether they fit, and search each one.

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