BenQ XL2735 144Hz – Occasional Missing Squares in Frame Skipping Test

[Fordahord]

Hi everyone,

I've been investigating some occasional micro-stuttering/judder on my BenQ Zowie XL2735 (1440p, 144Hz), particularly when turning the camera in games.

I decided to run the TestUFO Frame Skipping Test to check whether my monitor is actually skipping refreshes.

My test setup:

• Monitor: BenQ Zowie XL2735, 144Hz
• GPU: NVIDIA RTX 5080
• Browsers tested: Google Chrome and Microsoft Edge
• TestUFO showing 144Hz with the green READY indicator
• DyAc disabled
• Photos taken using an iPhone with a manual shutter speed of 1/8 second

I've taken multiple photos, and most show a continuous sequence of illuminated squares without any gaps.

However, approximately 1 out of every 10 photos shows an occasional missing square.

I also tested my dad's MSI monitor on a different PC, and I couldn't reproduce any missing squares there. Although, I realise that's not a completely controlled comparison.

I'm trying to understand whether these occasional gaps indicate genuine monitor frame skipping or whether they could simply be caused by browser frame-timing issues, Windows, or the camera.

I've also seen people mentioning that enabling V-Sync fixes similar results. However, I normally play competitive FPS games with V-Sync disabled because of the additional input latency.

My main questions are:

1. Is an occasional missing square (around 1 in 10 photos) considered normal in TestUFO?
2. Can the browser occasionally miss a frame even when TestUFO shows the green READY indicator?
3. Would genuine monitor frame skipping normally produce consistent gaps across multiple photos?
4. Does V-Sync need to be enabled for this test to be reliable, even if I keep it disabled when gaming?
5. Would using a longer camera exposure, such as 1/4 second instead of 1/8, help confirm whether frames are being skipped?

I'd appreciate any advice on whether this looks like an actual monitor issue or simply normal browser timing behaviour.

Thanks!

Photos showing the occasional missing squares:

skip3.jpg (90.71 KiB) Viewed 78 times

skip2.jpg (75.29 KiB) Viewed 78 times

skip.jpg (84.96 KiB) Viewed 78 times

[RealNC]

4. Does V-Sync need to be enabled for this test to be reliable, even if I keep it disabled when gaming?

Yes. Without vsync, there's no way to light up exactly one square on every refresh.

[kyube]

--snip--

Lower the refresh rate to 120 Hz with QFT applied. Here's a tutorial
Make sure to use backlight strobing with this model, as it leads to quite a substantial improvement in eye-tracked motion clarity.
Use Nvidia FastSync instead of Vsync if your FPS is ≥2x your frame rate in games you play. This is to eliminate tearing.
VSYNC isn't bad, nor does it add additional input latency if you know what you're doing. Your frame rate need to be below the refresh rate when using VSYNC.
This way you would eliminate tearing, but you wouldn't eliminate judder.
Judder is caused by a fractional ratio between the frame rate & refresh rate)
Tearing & judder (what you'll see mentioned online as "GSYNC fixes stuttering") are solved by going one of the following paths:
• Variable refresh rate path → GSYNC+VSYNC+Reflex or a custom frame rate limiter value which is 5-10% below the refresh rate. Effortless handling of both)
• Fixed refresh rate path → This one is trickier & requires choosing proper frame rate limiter values. Efficacy of this approach is likely slightly worse than path above.)

Hope this helps.