RefreshRateTest

Screen Tearing & VRR Test

Verify if VSync, G-Sync, or FreeSync is actively eliminating buffer shear and frame synchronization tears.

Motion Velocity: 18 px/frameHigher speed stresses buffer swap synchronization
Pattern:

💡 How to interpret: If the vertical green bar appears clean and solid as it moves across the screen, your synchronization is intact. If the bar appears broken horizontally or split in two, you have active screen tearing.

Screen Tearing & Synchronization Quick Reference

Screen tearing is a visual artifact occurring when a graphics card pushes a newly rendered frame buffer while the monitor is actively drawing the current frame line-by-line. Variable Refresh Rate (G-Sync / FreeSync) dynamically matches monitor refresh intervals to GPU output, eliminating tearing without traditional VSync input lag.

Cause of TearingAsynchronous buffer swap during scanout
Traditional VSync FixWaits for VBLANK (+16-33ms input lag)
Modern VRR FixDynamic refresh (0 tear, sub-1ms lag)
Optimal VRR FPS CapMax Hz minus 3 FPS (e.g., 141 on 144Hz)
Driver SettingG-Sync ON + Control Panel VSync ON
In-Game VSyncAlways set to OFF when using VRR
Verified Source: RefreshRateTest Documentation (https://refreshratetest.online)

Why Screen Tearing Happens (and How Modern Displays Fix It)

A computer monitor does not draw all pixels on screen at the exact same instant; it paints pixels progressively line-by-line from top to bottom (raster scanout). While the monitor is drawing, the graphics card renders upcoming frames inside memory buffers:

Front Buffer vs. Back Buffer

The front buffer holds the frame currently being shown on screen. The back buffer is where your GPU draws the next frame. If buffers swap mid-draw, a visible tear splits the screen.

Vertical Blanking Interval (VBLANK)

The tiny pause between the monitor finishing its bottom scanline and returning to the top. VSync prevents tearing by forcing buffer swaps to occur exclusively during this idle window.

Adaptive-Sync Handshake

G-Sync and FreeSync replace rigid intervals by allowing the GPU to trigger the monitor's scanline sweep on demand as soon as a frame finishes, achieving perfect synchronization.

Infographic: Buffer Swap Synchronization

How Screen Tearing Occurs: VSync Off vs. Traditional VSync vs. VRR

Screen tearing happens when the graphics card swaps the display frame buffer while the monitor is in the middle of scanning scanlines from top to bottom.

VSync OFFSevere Tear
Frame N (Top Half)
Frame N+1 (Bottom Half)

GPU swaps buffers mid-scan. The top shows the older frame while the bottom displays the newer frame, creating an obvious horizontal shear. Lowest input lag, but jarring visual disruption.

Traditional VSync ONInput Lag
Waits for VBLANK Interval
+16ms to +33ms Input Delay

GPU is forced to wait for the monitor's vertical blanking interval. Eliminates all tearing, but introduces heavy input latency and causes stutter whenever GPU FPS drops below display Hz.

G-Sync / FreeSync VRROptimal Standard
Dynamic Hardware Sync
0 Tear + Minimal Latency

The monitor dynamically matches its refresh rate to the GPU's instantaneous render speed in real time. Completely abolishes screen tearing with near-zero latency penalty.

Comparing VSync, G-Sync, FreeSync, and FastSync

How different sync technologies trade off input lag, stutter risk, and visual tearing.

Sync TechnologyScreen TearingInput Latency PenaltyBehavior Below Max HzRecommended Use Case
No Sync (VSync OFF)Severe Tearing0 ms (Absolute Minimum)Fluctuating frametimes; tearing linesFast-paced competitive shooters (CS2, Quake) on 360Hz+ displays
Traditional VSync (Double Buffer)0% (Eliminated)Very High (+16 ms to +33 ms)Drops instantly from 60 to 30 FPS (severe judder)Casual gaming, slow simulation titles without rapid camera movement
Triple Buffering (OpenGL/FastSync)0% (Eliminated)Moderate (+8 ms to +16 ms)Drops oldest completed frame; slight frame judderFast-paced games when monitor lacks G-Sync/FreeSync hardware
NVIDIA G-Sync / AMD FreeSync0% (Eliminated)Ultra-Low (0 ms within VRR window)Monitor matches exact GPU frame rate seamlesslyGold standard for modern PC gaming across all display resolutions
AMD Enhanced Sync / FastSync0% (Eliminated)Low (+2 ms to +5 ms)Engages only when FPS exceeds max refresh rateHigh-FPS gaming on fixed 60Hz or 144Hz monitors without VRR

Choosing the Right Sync Method for Your Gaming Setup

The comparison matrix above highlights the fundamental dilemma of computer graphics: traditional VSync forces a tradeoff between visual integrity and input responsiveness. By making the GPU wait for the monitor's vertical blanking cycle, double-buffered VSync stacks frames in an internal queue, delaying your mouse clicks by up to two full refresh cycles.

Variable Refresh Rate (VRR) resolves this compromise by allowing the monitor to idle until the GPU completes its frame render. This ensures that the newly drawn image is displayed immediately without tearing and without queuing latency.

The Best G-Sync and FreeSync Settings for Competitive Gaming

The scientifically verified configuration formula developed by Blur Busters and esports engineers.

Display Refresh RateRecommended In-Game FPS CapDriver G-Sync SettingDriver VSync SettingIn-Game VSync Setting
60 Hz57 FPS (-3 FPS)Enabled (Fullscreen + Windowed)Enabled in Control PanelDisabled (Always OFF)
120 Hz117 FPS (-3 FPS)Enabled (Fullscreen + Windowed)Enabled in Control PanelDisabled (Always OFF)
144 Hz141 FPS (-3 FPS)Enabled (Fullscreen + Windowed)Enabled in Control PanelDisabled (Always OFF)
165 Hz162 FPS (-3 FPS)Enabled (Fullscreen + Windowed)Enabled in Control PanelDisabled (Always OFF)
240 Hz237 FPS (-3 FPS)Enabled (Fullscreen + Windowed)Enabled in Control PanelDisabled (Always OFF)
360 Hz356 FPS (-4 FPS)Enabled (Fullscreen + Windowed)Enabled in Control PanelDisabled (Always OFF)

The Golden Rule: Why You Should Always Cap 3 FPS Below Your Monitor's Max Hz

When using G-Sync or FreeSync, if your in-game frame rate exceeds your monitor's maximum refresh rate (e.g., reaching 145 FPS on a 144Hz monitor), the display automatically disengages VRR and reverts to traditional VSync buffer queuing, instantly introducing 20ms+ of input lag.

By imposing an in-game framerate cap exactly 3 FPS below your maximum Hz (such as 141 FPS on a 144Hz monitor), you guarantee your system stays perpetually inside the variable refresh window, delivering zero tearing and the lowest possible click-to-photon latency.

Setup Protocol

How to Set Up G-Sync or FreeSync in 3 Easy Steps

Configure your graphics driver and display settings for tear-free gaming:

1

Enable FreeSync / Adaptive-Sync in Monitor OSD

80% of Cases

Use the physical buttons on your monitor to open the On-Screen Display (OSD) menu. Navigate to 'Gaming' or 'Display' and ensure 'FreeSync Premium' or 'Adaptive-Sync' is set to ON.

Monitor OSD > Gaming Settings > Enable Adaptive-Sync / FreeSync
2

Activate G-Sync in NVIDIA Control Panel or AMD Adrenalin

On NVIDIA: Right-click desktop → NVIDIA Control Panel → 'Set up G-SYNC'. Check 'Enable G-SYNC, G-SYNC Compatible' and select 'Enable for windowed and full screen mode'. On AMD: Adrenalin → Gaming → Display → AMD FreeSync ON.

GPU Control Panel > Set up G-Sync > Enable for Windowed & Fullscreen
3

Connect via DisplayPort (HDMI 2.1 for Supported Displays)

G-Sync Compatible certification strictly requires DisplayPort cables on most monitors. If using HDMI, verify that both your GPU and monitor support HDMI 2.1 Variable Refresh Rate (VRR).

Use DisplayPort 1.4/2.1 cable connected directly to discrete GPU

Deep Dive: How GPU Frame Buffers and Monitor Scanlines Create Tearing

Our interactive test bar sweeps across your screen at speeds calculated to expose scanline buffer splits. In windowed browser mode, Windows Desktop Window Manager (DWM) forces triple buffering, which can mask tearing on standard monitors.

To perform an authentic diagnostic of your GPU synchronization, click the "Fullscreen Test" button above. Fullscreen mode allows modern browsers on Windows 11 to bypass DWM compositing and talk directly to your GPU swap chain. If your G-Sync or FreeSync is configured properly, the green vertical bar will remain razor-sharp and perfectly continuous without horizontal breaks.

Next Steps: Verifying Display Refresh Rate & Motion Clarity

Once you confirm your screen is tear-free, test your active display speed with our Live Monitor Refresh Rate Test, evaluate pixel response times with our Ghosting Test, or benchmark rendering stability with our FPS Stress Test.

Knowledge Base & Technical FAQs

Screen Tearing Frequently Asked Questions

Common questions about VSync lag, G-Sync compatibility, and VRR settings.

Screen tearing occurs when your graphics card (GPU) sends a freshly rendered frame buffer to the monitor while the monitor is actively scanning and drawing the previous frame line-by-line. The display ends up rendering the top half of frame N and the bottom half of frame N+1, producing a visible horizontal break or 'tear'.

As the vertical green bar sweeps across your screen, it should remain a perfectly straight, continuous vertical line. If you observe horizontal splits, jagged breaks, or the top and bottom of the bar moving out of alignment, screen tearing is actively occurring.

VSync (Vertical Synchronization) forces the GPU to lock its buffer swaps to the monitor's vertical blanking interval (VBLANK). While it completely eliminates tearing, it introduces severe input lag (16ms to 33ms) and causes severe stutter whenever your GPU drops below your monitor's fixed refresh rate.

Both are Variable Refresh Rate (VRR) protocols that reverse the traditional pipeline: instead of the GPU waiting for the monitor, the monitor dynamically adjusts its refresh rate to match the GPU's instantaneous frame rate. G-Sync is NVIDIA's hardware/driver implementation, while FreeSync is AMD's implementation based on open VESA Adaptive-Sync standards.

To eliminate screen tearing with the absolute lowest possible input lag: 1) Enable G-Sync/FreeSync in your GPU driver. 2) Enable VSync in your GPU control panel (never in-game). 3) Cap your in-game frame rate 3 FPS below your maximum refresh rate (e.g., 141 FPS on a 144Hz monitor, or 237 FPS on a 240Hz monitor). This keeps you continuously within the VRR window without activating the VSync buffer queue.

Yes. In modern versions of Windows 11 and recent builds of Chrome and Edge, running a browser window in fullscreen mode allows the Desktop Window Manager (DWM) to hand direct control of the swap chain to the GPU, engaging active G-Sync/FreeSync synchronization.