Refresh rate and frame rate comparison

What you’re watching

Each row moves the same shape at the same speed, but only updates it at its own frame rate, so slower rates move in bigger jumps: at 960 px a second, 32 px per frame at 30 fps and 2.7 px at 360 fps. Every step is timed to your screen’s refreshes, not a clock, so the comparison measures your refresh rate first and then labels each row exact, uneven or slowed. If a fast screen shows 60, the refresh rate test lists the usual causes.

Why it sometimes runs slowed

Your screen can show at most one new frame per refresh, so a 60 Hz screen can’t show 120 fps at real speed. When the fastest row is faster than your screen, everything slows down by the same amount instead. The rows then play as if on a 720 Hz screen, the lowest rate that’s a multiple of all six, and each refresh of your screen shows one of its refreshes, so every row stays exact. That means 12x slower on 60 Hz, 6x on 120 Hz, 5x on 144 Hz, 3x on 240 Hz, and real speed from 360 Hz up. Slowed down, each row still jumps the true distance of one frame, but you don’t see the real smoothness or blur.

Rates your screen shows evenly

At real speed, a rate moves evenly only if it divides your refresh rate: at 60 fps on a 120 Hz screen, each frame gets exactly two refreshes. At any other rate some frames stay up longer than others, which you see as judder, and that row is labeled uneven. From 24 fps up, these are the rates common screens show evenly:

• 60 Hz. 60 and 30 fps.
• 120 Hz. 120, 60, 40, 30 and 24 fps.
• 144 Hz. 144, 72, 48, 36 and 24 fps, but neither 60 nor 30.
• 165 Hz. 165, 55 and 33 fps, and none of 24, 30, 60 or 120.
• 240 Hz. 240, 120, 80, 60, 48, 40, 30 and 24 fps.
• 360 Hz. 360, 180, 120, 90, 72, 60, 45, 40, 36, 30 and 24 fps.

The comparison shows what each rate looks like, not what your computer can reach. A game runs on its own clock, and the FPS test measures the frame rate you actually get.