Demo of the audacity of Javascript-based beam racing. Only successfully tested on Windows in Chromium browsers, using a special command line.
You may copy and paste this Windows command line for convenient startup of Chrome in VSYNC OFF mode:

"C:\Program Files\Google\Chrome\Application\chrome.exe" --user-data-dir=c:\windows\temp\vsync-off --disable-gpu-vsync --disable-frame-rate-limit https://testufo.com/raster51

1. Temporarily use SINGLE MONITOR (disable multimonitor) and LOWER REFRESH RATE at 60 Hz or less for more accurate beam racing.
2. Wait for refresh rate to be detected. Alternatively, use TestUFO Refresh Rate.
3. Configure your GPU and operating system to permit VSYNC OFF.
       NVIDIA Control Panel -> Manage 3D Settings -> Global -> Vertical Sync -> "Use 3D Application Setting"
4. Relaunch Chrome using blue command line above.
5. If necessary, manually enter exact refresh rate of your display. Animation works best at low Hz.
6. Hit F5 at least twice to refresh the page. This helps power management settle down to high frameslice rate.
7. Click full screen button in upper-right corner of animation.
8. If animation is misaligned vertically, use mouse to drag white bar (VBI) to top or bottom of screen.
9. If tearing correctly at over ~1000fps, you will see wavy lines (video) & mouse softcursor will have less lag than OS mouse pointer.

TIPS ON SYSTEM SETTINGS: This animation performs best at lower refresh rates (24Hz or 60Hz) using the WebGL engine, in Performance Mode (not Balanced Mode), on Windows systems with AMD/NVIDIA GPUs, with MSI Afterburner forcing a high idle GPU clock rate. Modern high performance GPUs (GTX 1080 and newer) should be able to achieve 2000-4000fps on current CPUs. Currently only tested on Windows systems with high performance NVIDIA GPUs. For more information on this new browser beamracing feat, see pouet.net thread and vogons.org thread #1 / thread #2, as well as our github open source RefreshRateCalculator.js