Understanding Motion Blur Reduction: A Deep Dive into ELMB, DyAc, and ULMB

Introduction: The “144Hz is Blurry” Myth

Many gamers upgrade to a 144Hz or 240Hz monitor expecting a perfectly sharp, crystal-clear experience. However, upon loading their favorite fast-paced shooter, they are often disappointed to find that moving objects still appear “smeared” or “soft.”

This frustration is caused by a fundamental engineering challenge: Motion Blur. Even if your monitor’s pixels are extremely fast, the way modern LCDs display images creates blur on your retina. In this guide, we will explore the science of Persistence, why the “Sample-and-Hold” method is flawed, and how proprietary technologies like ASUS ELMB and BenQ DyAc aim to bring back the legendary motion clarity of old CRT monitors.

1. The Physics of Blur: Sample-and-Hold vs. Impulse

To understand motion blur reduction, we first have to understand why it happens in the first place.

The Sample-and-Hold Problem

Almost all modern LCD panels (IPS, VA, TN) and OLEDs use a “Sample-and-Hold” display method. This means a frame is drawn on the screen and stays perfectly static until the next frame is ready. While the screen image is static, your eyes are constantly moving to track the moving object. This creates a mismatch between what your eyes expect and what the screen is doing, resulting in a blurred image smeared across your retina.

The Impulse Solution (The CRT Legacy)

Old CRT (Cathode Ray Tube) monitors didn’t have this problem. They worked on an “Impulse” basis—they would flash the image for a tiny fraction of a millisecond and then go black. This “strobe” perfectly matches how human vision tracks motion, providing near-perfect clarity. Motion Blur Reduction technologies are essentially trying to make high-tech LCDs act like low-tech CRTs.

2. MPRT vs. GtG: The Two Faces of Speed

Manufacturers love to splash “1ms Response Time” on the box, but they rarely tell you what they are measuring.

• GtG (Gray-to-Gray): This measures how fast a pixel can physically shift from one color to another. Low GtG reduces “ghosting” (trails behind objects).
• MPRT (Motion Picture Response Time): This measures persistence—how long a pixel is visible to your eye. Even an “0.1ms GtG” OLED will still look blurry if its MPRT is high. Motion blur reduction technologies prioritize lowering MPRT.

3. Backlight Strobing: How It Works

The most common method of blur reduction is Backlight Strobing, often called BFI (Black Frame Insertion) in the TV world.

The Mechanism

Instead of leaving the backlight on constantly, the monitor turns the light OFF while the pixels are transitioning between frames. It only turns the light ON once the pixels have finished their move and the image is stable. By hiding the “transition” phase and showing only the “stable” phase in a quick flash, the perceived motion becomes significantly sharper.

Industry Names for Strobing:

Each manufacturer has its own marketing jargon for this technology:

• ASUS: ELMB (Extreme Low Motion Blur)
• BenQ: DyAc (Dynamic Accuracy)
• NVIDIA: ULMB (Ultra Low Motion Blur)
• Gigabyte: Aim Stabilizer
• MSI: Anti-Motion Blur

4. The “Catch”: Trade-offs and Downsides

There is no such thing as a free lunch in display engineering. Using motion blur reduction comes with three significant drawbacks:

A. Loss of Brightness

Because the backlight is turned off for half the time (or more), the overall screen brightness drops significantly. Some monitors become too dim to use in a well-lit room when ELMB or DyAc is enabled.

B. Flicker and Eye Fatigue

Strobing is effectively high-speed flickering. While you can’t see the individual flashes, many users report headaches, dry eyes, or “flicker fatigue” after long gaming sessions. People with sensitive vision or epilepsy should use these technologies with caution.

C. Strobe Crosstalk

If the timing of the strobe doesn’t perfectly match the pixel transition, you get Strobe Crosstalk—a “double-image” effect that can be more distracting than the original blur. High-end monitors (like BenQ’s “Zowie” series) allow you to manually tune the strobe timing to minimize this.

5. VRR Compatibility: The Holy Grail

Historically, you couldn’t use Variable Refresh Rate (G-Sync/FreeSync) and Motion Blur Reduction at the same time. If your FPS fluctuated, the strobe would fall out of sync, causing massive flickering.

However, we are now seeing “Sync” technologies like ASUS ELMB-Sync, which allows for both crystal-clear motion and tear-free gaming simultaneously. This requires advanced timing controllers and is usually only found on premium gaming displays.

6. How to Test Your Blur Reduction

How do you know if your settings are actually making a difference? You need a “stress test” for your eyes.

Our Motion Test Tool features a tracking test.

1. Turn your Blur Reduction (ELMB/DyAc/ULMB) OFF. Try to read the text on a moving object.
2. Turn it ON. Notice how the text suddenly becomes legible and sharp.
3. Check for “Strobe Crosstalk” by looking for ghost images behind the main object.

Summary: Should You Use It?

Motion blur reduction is a powerful tool for the competitive gamer, but it requires a high-end monitor and a willingness to trade some brightness for raw clarity.

Check your current refresh rate and motion capabilities with our Screen Info Tool to see if your hardware supports these advanced features!