Tech glossary

A processor with eight cores can genuinely do eight things at once. More cores help when you run many programs together, or with work that splits up cleanly — rendering, compiling, exporting video.

Watch out: More cores do not make a single program faster. Most games and most everyday software lean on a handful of fast cores, so a 6-core chip with high clocks often beats a 16-core one at them.

Most modern cores handle two threads at once, filling gaps when one stalls waiting for memory. An 8-core chip usually reports 16 threads.

Watch out: Sixteen threads is not sixteen cores, and a listing that quotes only threads is flattering itself.

Within one processor family, higher is faster. Boost clock is the peak a chip reaches briefly; base clock is what it sustains when all cores are loaded and warm.

Watch out: Comparing GHz across different generations or brands tells you very little. A 3.5GHz chip from this year beats a 4.5GHz one from eight years ago at nearly everything.

Fine for office work, browsing, video and light photo editing. Shares system memory rather than having its own.

Watch out: Not a substitute for a graphics card in games or 3D work, whatever the box says.

A motherboard takes one or the other — never both. DDR5 is faster and comes in larger sticks; DDR4 is cheaper and still perfectly good for most work.

Watch out: This is the single most common upgrade mistake. Check the board before buying memory; our upgrade advisor does it for you.

Desktop sticks are longer and will not fit a laptop. Many thin laptops solder some or all of their memory to the board, which makes it unupgradeable.

Watch out: A laptop advertised as '16GB, upgradeable to 32GB' may have 8GB soldered and one free slot. Ask which.

Two 8GB sticks are meaningfully faster than one 16GB stick, because the processor can talk to both at once. It matters most with integrated graphics, which borrow system memory.

Plugs directly into the motherboard's PCIe lanes rather than going through the old drive interface. Several times faster than a SATA SSD at moving large files.

Watch out: The headline 'up to 7,000 MB/s' is a burst figure on an empty drive. Sustained writes on a full drive can be a fraction of it, and for opening apps the difference against a good SATA SSD is barely noticeable.

Used by 2.5-inch SSDs and by all mechanical hard drives. Slower than NVMe but entirely adequate for storage you are not booting from.

A short slot on the motherboard that a stick-shaped drive screws into. An M.2 drive may be NVMe or SATA — the shape does not tell you which.

Watch out: 'M.2 SSD' on a spec sheet is not a promise of NVMe speed. Look for the word NVMe.

Holds textures and frame data. Running out of it causes stutter that no amount of system memory fixes.

Watch out: A cheap card with a lot of VRAM is usually still a cheap card. VRAM only helps once the chip is fast enough to need it.

Quoted in watts. Used to size a cooler and, loosely, a power supply.

Watch out: It is not power draw. Modern processors and cards routinely exceed their TDP under boost, sometimes by half again. Size a power supply with headroom, which our builder does.

IPS gives accurate colour and wide viewing angles, and is what you want for most work. VA has deeper blacks. TN is fastest and cheapest but the colour shifts as you move your head.

60Hz is standard; 120Hz and above look noticeably smoother in motion, in games and in scrolling alike.

Watch out: A high refresh rate does nothing if the machine cannot produce that many frames.

250 nits is typical indoors. 400 or more is worth having if you sit near a window; below 250 struggles in daylight.

On this site it means a machine that has been through the bench: checked, cleaned, and listed with the specification it actually has rather than the one it shipped with years ago.

Watch out: The word is unregulated and means different things at different shops. Ask what was tested and what warranty comes with it — and if a shop cannot answer, that is the answer.

The only honest way to compare two parts for speed.

Watch out: We do not publish benchmark figures, because we have not measured them and licensing someone else's corpus is not the same as having tested the machine in front of you. Any shop quoting scores it did not measure is quoting marketing.

Usually the processor limiting a graphics card, or the reverse, depending on the work.

Watch out: Bottleneck percentages from online calculators are close to meaningless — the answer depends entirely on the workload, resolution and settings. Ours says 'estimate' on the screen for that reason.