Input Lag Test

This test measures the time between a click event firing in JavaScript and the next requestAnimationFrame callback — the browser-level click-to-render latency. It captures how quickly the browser processes your input and schedules a repaint. This is a component of total system input lag, but does not include OS-level input processing, GPU rendering time, display panel latency, or the display's pixel response time. Think of it as the software layer of input lag, separate from hardware latency.

Total system input lag is the time from a physical input (mouse click, key press) to the corresponding visual change appearing on screen. It includes: (1) Hardware input processing (~0.5–1ms for modern USB mice). (2) OS interrupt handling and driver processing (~1–5ms). (3) Application processing and render scheduling (~1–8ms — what this test measures). (4) GPU rendering and frame pipeline (~1–3ms at 60FPS). (5) Display output lag (monitor processing, ~1–30ms depending on display and mode). (6) Pixel response time (~0.1–5ms). Total input lag on a gaming PC with a fast monitor typically ranges from 5–20ms total.

Under 4ms is excellent — your browser is processing input and scheduling renders very efficiently. 4–8ms is good and represents typical performance on a modern machine. 8–16ms is acceptable — corresponds to roughly one frame at 60–120Hz. Over 16ms suggests the browser may be under load, hardware acceleration may be disabled, or background processes are competing for resources. For context, human perception of input lag begins around 50ms for most users, though competitive gamers can detect differences of 10–15ms under controlled conditions.

To minimize total input lag: (1) Use a high refresh rate monitor (240Hz halves per-frame lag vs 120Hz). (2) Enable your monitor's Game Mode or Low Latency Mode. (3) Use DisplayPort instead of HDMI where possible (lower processing path). (4) Set your monitor's overdrive to an appropriate level. (5) Use a high polling rate mouse (1000Hz or 8000Hz). (6) Disable VSync and use G-Sync/FreeSync instead to eliminate VSync stutter without adding lag. (7) Keep GPU drivers updated. (8) Ensure the game runs at high enough FPS to utilize the monitor's refresh rate.

Browser input lag varies due to several factors: (1) JavaScript garbage collection pauses — memory cleanup causes brief freezes. (2) Browser compositor thread scheduling — the browser balances rendering with other tasks. (3) OS process scheduling — background tasks compete for CPU time. (4) Thermal throttling — on laptops under sustained load, the CPU may throttle. (5) Power saving modes — battery saver and Windows power plan settings cap performance. For the lowest and most consistent results, close background tabs, disable battery saver, and ensure hardware acceleration is enabled in browser settings.

Yes. Chromium-based browsers (Chrome, Edge, Brave) typically show the lowest and most consistent results due to their advanced compositor threading and V8 JavaScript engine. Firefox has historically shown slightly higher variance due to its different rendering architecture. Safari on macOS is optimized for Apple hardware and often shows very competitive results. The differences are typically 1–3ms, which is below human perception. All modern browsers benefit from hardware acceleration — verify it's enabled for the most accurate results.

Higher resolutions increase the GPU workload for rendering, which can add marginal frame latency — but modern discrete GPUs handle 1440p and 4K at minimal additional cost. The more significant factor is your monitor's input processing pipeline: some displays add 20–50ms of image processing lag that cannot be measured in-browser. Enable Game Mode or Low Latency Mode on your display to bypass image processing and minimize display-side lag.

No. Input lag refers to the local delay between your physical input and the visual response on your own screen. Network latency (ping) is the round-trip time for data to travel to a game server and back. In online games, both contribute to perceived responsiveness. You might have 1ms input lag but 80ms ping, meaning your local click registers instantly but the game server takes 80ms to respond. This test measures only the local browser input lag component.

The test measures browser-level latency, not hardware input processing. A 8000Hz polling rate mouse won't significantly change this score because the bottleneck here is the JavaScript event loop and browser rendering pipeline, not how fast the mouse reports to the OS. However, a high polling rate mouse will reduce total system lag in games. To reduce this test's score specifically, focus on browser settings: enable hardware acceleration, close background tabs, and use a high-performance power plan.