This is the pen latency test of the iPad Air 4, which uses a 60 hertz display versus the Samsung tab, s7 plus, which uses 120 hertz display. So the animation of the line that's appearing on the iPad Air 4 seems to be a bit more choppy and the gap between the line and the pen tip is noticeably larger. The app I'm using here is Wacom bamboo paper for the next comparison, I'll be using the default notes app. So it's apple notes on the left and Samsung notes on the right. I do not know the exact specifications for the latency, but from this test from what I can see, there is almost no gap between the line and the pen tip with the Samsung tablet and the Samsung s pen, with the Apple Pencil 2 and the iPad Air 4. There is a noticeable gap, and this app I'm using now is a vector drawing app if you notice, I'm flickering on the Samsung tablet.
That's because the AMOLED display that Samsung is using actually uses pulse wave modulation, whereas with the iPad f4, it's just standard LCD, which is not affected by PWM. Latency is also affected by how well the app is programmed. So here we've Autodesk sketchbook. I can see a huge gap between the line and the pen tip on the Samsung tablet. The animation of the line that appears is still smoother compared to the iPad airflow, but the gap on both tablets still very noticeable.
Source : Teoh on Tech