What Is the Monitor Refresh Rate & Ghosting Test?
Monitor ghosting is a visual artifact where moving objects leave faint trailing shadows behind them, caused by LCD liquid crystal molecules not transitioning fast enough between pixel states. This test uses a high-precision animation loop calibrated to the standard 960-pixels-per-second benchmark used by professional display reviewers. Three contrast lanes (high, medium, low) make ghosting artifacts visible across different background colors, matching real gaming conditions.
How It Works
The tool uses requestAnimationFrame with high-precision timestamps to drive a Canvas 2D rendering loop. The frame time between rAF callbacks is used to measure your browser's actual frame interval, deriving the real display refresh rate. The UFO object moves at a configurable velocity (default 960px/s), which matches the international MPRT (Moving Picture Response Time) standard used by display testing labs.
Step-by-Step Instructions
Technique Tips & Hardware Facts
GtG vs. MPRT
Gray-to-Gray (GtG) measures the crystal switching time in isolation. MPRT (Moving Picture Response Time) measures perceptual blur including sample-and-hold, which is what matters for gaming. At 60Hz a monitor needs sub-7ms GtG to minimize motion blur.
Overdrive Settings
Monitor overdrive (Response Time = Fast/Faster/Fastest/Extreme in OSD) applies extra voltage to speed up transitions. Too much overdrive causes "inverse ghosting" — a bright halo in front of moving objects. Tune your overdrive to eliminate trailing blur without creating coronas.
Higher Hz, Less Blur
At 240Hz, each frame lasts only 4.17ms. This fundamentally reduces sample-and-hold blur regardless of GtG, which is why 240Hz monitors feel sharper in motion than 144Hz monitors even with similar pixel response times.
ELMB / ULMB Strobe
ASUS ELMB and NVIDIA ULMB introduce backlight strobe synchronization that can eliminate sample-and-hold blur at supported refresh rates. Enable this when testing your monitor's maximum motion clarity.
Frequently Asked Questions
What refresh rate does this tool measure?
It measures the rate at which your browser dispatches requestAnimationFrame callbacks — typically the monitor's native refresh rate. Most browsers cap rAF at the display's native Hz for power efficiency.
Why does the UFO look blurry even on a fast monitor?
Smooth-pursuit eye tracking while following a moving object causes biological motion blur (saccadic suppression) in your visual cortex. This is partially independent of monitor hardware. The blur you see when your eyes don't track perfectly is primarily monitor-induced.
What is the 960px/s velocity standard?
The 960 pixels-per-second benchmark was established by Blur Busters as a standard for comparing ghosting across different monitors. It provides a consistent velocity that shows ghosting artifacts without being so fast that subpixel analysis is impossible.
Can I test FreeSync/G-Sync variable refresh rate with this?
Partially. The rAF loop runs at your display's current Hz. If VRR is engaged and the Hz changes, the animation speed adjusts automatically. However, specific VRR testing (variable frame pacing) requires dedicated tools.