Mouse dropping effect (phantom array) still exists at 144Hz

Discuss BENQ Blur Reduction (strobe backlight) and the Blur Busters Strobe Utility. For Z-Series monitors (V2 firmware) on XL2411Z, XL2420Z and XL2720Z.

Mouse dropping effect (phantom array) still exists at 144Hz

Postby HOLECHIEN87 » 10 Jul 2017, 21:27


see the cursor. i took this pic with a camera. i thought this phenome should not appear.. what the purpose of having 144hz if i see that?

can someone explain me if it's normal, if you'r tool improve it. i'm really confused right now i bought this monitor (xl2411z) for gaming and especially to avoid this kind of stuffs????

edit : i moved my cursor fast to have this result
Posts: 6
Joined: 07 Jul 2017, 22:28

Re: Isn't this kind of things i should not have with a benq

Postby RealNC » 11 Jul 2017, 06:04

If you mean the gaps between each cursor position, then you need to compare it to 60Hz. Just taking a picture in 144Hz doesn't tell you anything.
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.
User avatar
Posts: 1114
Joined: 24 Dec 2013, 18:32

Re: Isn't this kind of things i should not have with a benq

Postby Haste » 11 Jul 2017, 06:20


This phenomenon is called the phantom array effect.

Each cursor that you see correspond to one frame/refresh.

The faster the frame rate/refresh rate, the higher the number of cursors and the closer they appear together.

144Hz (while better than 60Hz) is still significantly too slow to prevent that issue when things are moving fast on the screen.

I'm afraid, until we get monitors that refresh at 4 digits refresh rates, we are stuck with that artifact.

This video illustrates it very well:

phpBB [video]

Notice how it gets better as the refresh rate gets higher. But even at 180Hz, it's still very noticeable.
Monitor: Asus ROG Swift PG278Q
Posts: 279
Joined: 22 Dec 2013, 09:03

Mouse dropping effect (phantom array) still exists at 144Hz

Postby Chief Blur Buster » 11 Jul 2017, 16:15

Unfortunately, the phantom array effect (stroboscope style stepping effect, also known as the "wagon wheel effect") is visible all the way to approximately 10000 Hz (ten thousand Hertz), depending on circumstances.

(From lighting industry paper about flicker of fluorescent ballasts and ultra-high-frequency PWM)

While this is a lighting industry paper, it illustrates the unobtainium refresh rates needed to truly eliminate certain kinds of display artifacts (without things like artificially-added motion blur). Finite refresh rates (even 240Hz, 480Hz, etc) create display artifacts indirectly, such as -- that improve gradually but doesn't disappear until unobtainium refresh rates -- diminishing points of return. But certain artifacts like mouse phantom arraying is still easy to see even on 240Hz displays, even if the distance between arrows at 240Hz would be 1/4th as much as at 60Hz.

The higher refresh rates you go, the better for the mouse effect. At 144Hz versus 60Hz, it's only 60/144ths the distance between mouse cursor position (in two consecutive refresh cycles) at 144Hz versus 60Hz. However, if you move your mouse pointer at 8000 pixels per second (a common flick speed -- a screen width in a fraction of a second), you would need 8000Hz to fill each pixel position with a mouse arrow, for a continuous blur rather than phantom array.

You do get many benefits of 144Hz, over 60Hz, however.

  • Reduced amount of motion blur, see
  • The gaps between mouse arrow pointers will still shrink, proportionally to the refresh rate.
  • Higher Hz do have reduced input lag at higher refresh rates, see our input lag tests of different refresh rates at GSYNC 101: Input Lag and Optimal Settings. Although this is a GSYNC 101, it also tests the lag of non-GSYNC refresh rates too.
  • In addition, your monitor might also include a Blur Reduction backlight for clearer motion, see Motion Blur Reduction Backlights for more info -- but that won't solve the phantom array effect. Most 144Hz and better monitors have a blur reduction feature.

NOTE ABOUT MOTION BLUR MATH: Going ever higher refresh rates, while has points of diminishing returns, has effects on motion artifacts go far beyond what most humans expect. Ignoring GtG additions to blur (very small factor on 1ms TN 144Hz monitors with 6.9ms refresh cycle visibility times) and ignoring strobe-based blur reduction -- on continuously-illuminated (non impulse/non strobed/non CRT) sample-and-hold displays -- the display motion blur scales exactly linearly with frame visibility time. Assuming the perfect zero-GtG sample-and-hold display. Even 0ms instant pixel response still creates motion blur due to the sample-and-hold effect. Modern TN gaming monitors (at least with good balanced overdrive) tends to roughly resemble the ideal Blur Busters Law of "1ms of frame visibility time equals 1 pixel of motion blur for every 1000 pixels/second of motion" -- found in 60Hz vs 120Hz vs LightBoost. As a result, 120 frames per second has half the motion blur of 60 frames per second. And 240 frames per second has one-quarter the motion blur of 60 frame per second. Display motion blur is mathematically proportional to length of frame visibility time. At low frame rates, this is visible stutter/judder. At high frame rates, the stutter/judder blends into motion blur. The higher the Hz you go, the thinner the motion blur becomes. For educational animations I've created about this phenomenon, see and ... Frame visibility duration time is also why non-strobed OLED displays still have motion blur, even if their pixel response is more instantaneous than LCD. The only way to reduce motion blur during eye tracking situations, is to reduce frame visibility time -- either by increasing frame rates or refresh cycles (more frames) -- or by adding black periods between frames or refresh cycles (such as strobing). Now, however, for the phantom array effect -- aka mouse droppings -- the only solution to truly solve that, is to add WAY more fully visible frames (thousands of refresh cycles per second needed) or adding artificial motion blurring to the mouse arrow pointer (which isn't desirable).

TL;DR: The mouse dropping effect becomes less at higher refresh rates, but still exists even at extremely high refresh rates, even at several thousands of Hertz. That said, you get other important advantages of high refresh rates.
Head of Blur Busters - | | Follow @BlurBusters on Twitter!
User avatar
Chief Blur Buster
Site Admin
Posts: 3310
Joined: 05 Dec 2013, 15:44

Return to BENQ Blur Reduction & Strobe Utility

Who is online

Users browsing this forum: No registered users and 3 guests