How sharp is motion at 60, 144 or 240 Hz?
When your eye tracks a moving object, every static frame smears across its hold time. Blur equals speed times hold time: doubling the frame rate halves it, while more resolution does not help.
Settings
What your eye sees
LCD (IPS, VA)OLED
The images are still captures of what your eye sees while tracking the object. That is why your own monitor shows them correctly, even at 60 Hz. Response times are class values: IPS 5 ms, VA 9 ms, OLED 0.1 ms.
Head-to-head comparisons
- 60 vs 144 Hz 60 Hz vs 144 Hz side by side: how much motion smears on IPS and VA. With numbers for hold time, response time and fps.
- 144 vs 240 Hz 144 Hz vs 240 Hz side by side, IPS and OLED: why response time holds IPS back and when 240 Hz is really sharper.
- 240 vs 360 vs 480 Hz 240, 360 and 480 Hz OLED side by side: how much sharper fast motion still gets and how many fps you need for it.
Where the blur comes from
A monitor does not show fluid motion but a sequence of still frames. Each one stays until the next arrives (sample and hold). Your eye, however, keeps tracking a moving object smoothly. While a frame stands still, your gaze sweeps across it, and the frame smears on your retina.
So the blur width is simply speed times hold time. At 960 px/s and 60 Hz that is 16 px, at 240 Hz only 4 px. LCDs add the response time of their pixels, OLEDs practically do not.
Measured in visual angle instead of pixels, resolution cancels out. A 4K monitor shows the same blur, just with more pixels. Sharper motion only comes from a shorter hold time: more Hz and fps, or strobing.
Blur [px] = speed [px/s] × hold time [s]Hold time = 1 / min(fps, Hz)Blur [°] = eye tracking speed [°/s] × hold time
Frequently asked questions
Is 144 Hz worth it over 60 Hz?
Yes, it is the most noticeable step. Each frame stays 6.9 instead of 16.7 ms. Scrolling at 960 px/s, blur on an IPS monitor drops from 22 to 12.7 px, pixel response time included. Your PC needs to deliver around 144 fps. On the desktop and when scrolling it almost always does; in games it depends on your graphics card.
Is 240 Hz visibly sharper than 144 Hz?
Yes, if your fps keep up. The hold time drops from 6.9 to 4.2 ms. On IPS, pixel response time holds it back, though: at 960 px/s blur only drops from 12.7 to 10 px, while a 240 Hz OLED gets down to 4.1 px. If your games only run at 144 fps, each frame still stays 6.9 ms on a 240 Hz monitor.
Why is an OLED sharper than an IPS monitor at the same refresh rate?
OLED pixels switch in well under a millisecond, LCD pixels typically need 5 to 10 ms. That response time adds blur on top of the hold time. The sample-and-hold blur itself is the same for both.
Does 4K or 1440p make motion sharper?
No. More pixels make still images sharper, but not motion. In visual angle, blur is eye tracking speed times hold time, and resolution plays no part.
What does strobing do (ULMB, DyAc, black frame insertion)?
Each frame lights up only briefly, about 1 ms, and stays dark for the rest of the time. Motion then looks as sharp as at roughly 1000 Hz. The cost: lower brightness, possible flicker, and double images when your fps are below the refresh rate.
Why does the comparison work on my 60 Hz monitor?
The images do not move. They are pre-calculated captures of what your eye sees on each monitor. Your own monitor only has to show them as still images.