Visual discontinuity inspection
This screen tearing test moves high-contrast vertical bars, a checkerboard, or a horizontal grid continuously across the browser surface. It can help you inspect a visible split or motion discontinuity, but it cannot certify a synchronization feature or diagnose the display path.
Three spatial references
Alternating light and dark bars provide long vertical edges. Follow one edge while it moves. A classic tear-like observation is a horizontal boundary where the upper and lower portions appear laterally displaced during the same visible update.
The checkerboard adds both horizontal and vertical references. It can make a spatial break conspicuous, but its fine contrast may also reveal scaling, pixel response, moiré in camera footage, or tracking blur that is not screen tearing.
The grid provides repeated rows and wider vertical divisions. Use the amber center reference to compare alignment as the plane passes it. Vary speed gradually; the page avoids rapid luminance flashing and changes only horizontal position.
performance.now() marker. It confirms that the browser animation is advancing; it is not a scanout-position probe.Similar symptoms, different mechanisms
Screen tearing traditionally describes portions of different frames visible at once, often separated by a horizontal boundary. A browser may prevent that presentation path, so this tool is best understood as an opportunity to inspect—not a way to force—a tear.
Stutter is uneven motion over time, such as a held, repeated, or late frame. It may look like a jump without the displaced horizontal boundary associated with tearing. Thebrowser cadence estimator can add timing context, though it still cannot measure end-to-end frame delivery or input latency.
A trail that follows an object is closer to ghosting, overdrive behavior, or persistence blur than to a split image. Use the dedicated ghosting workflow to change transition polarity, object size, and background while leaving this test focused on alignment.
Confirm refresh and VRR configuration through current operating-system, GPU, game, and monitor information. Those sources can report settings the browser cannot read. A rigorous end-to-end assessment may also require controlled capture hardware or instrumentation.
No. Modern browsers commonly use synchronized compositing, which can suppress visible tearing independently of FreeSync, G-Sync, or another VRR state. Absence of a tear is an observation in this browser path, not a VRR confirmation.
No. The page neither reads the monitor’s negotiated range nor controls presentation with the precision needed to map its limits. Use verified system or display information for configuration, and dedicated measurement methods for characterization.
A dropped or repeated frame can create a jump; uneven frame pacing can create stutter; pixel response can soften an edge; scaling can disturb fine grids; and video capture can introduce rolling-shutter bands. Repeat across patterns before choosing a description.