Chroma subsampling (4:4:4 vs 4:2:0)
Also searched as: chroma subsampling · 4:4:4 · 4:2:0 · 4:2:2 · 444 vs 420 · color compression
What it means
Chroma subsampling is a bandwidth-saving trick: the display keeps full detail in brightness (luma) but throws away some of the color (chroma) detail. 4:4:4 keeps full color for every pixel; 4:2:2 and 4:2:0 keep less color information to fit through a cable with limited bandwidth. Your eyes are far more sensitive to brightness than to fine color, which is why the lower modes are often hard to notice at all.
More detail
Where it does show up is on sharp, high-contrast color edges — most of all small colored text on the desktop, which can look fringed or smeary at 4:2:0. In actual game scenes and video, 4:2:0 is usually very hard to tell apart from 4:4:4, so it matters far less for gaming than for desktop reading. …
In the Blackbook
The deeper explanation continues inside the app. The Blackbook publishes its verdicts here — the full write-ups stay in the book, on your rig, next to your own measurements.
The Compy Blackbook holds 191 graded entries like this one, judged against your hardware — and every change it does make is reversible, with the receipt to prove it.
See Compy →