Free UFO Tester Tool
Motion Monitor Blur & Ghosting Checker
Test your monitor's motion blur, pixel ghosting, refresh rate accuracy, frame pacing and display smoothness — all free, right in your browser. Works with 60Hz, 75Hz, 120Hz, 144Hz, 165Hz, 240Hz and 360Hz monitors.
Side-by-side comparison showing how 30, 60, 144 and 240 FPS look on your monitor simultaneously. The difference in motion clarity is immediately visible.
What Is the UFO Motion Test?
The UFO motion test is a browser-based monitor test that moves objects (UFOs) across your screen at a precise speed and frame rate. It is the most widely used visual test for checking monitor motion blur, ghosting, refresh rate accuracy and pixel response time — all without installing any software.
The test was originally developed by Blur Busters and has become a standard reference in the display testing community. Our version adds six dedicated test modes, real-time Hz detection, ghosting estimation, and a side-by-side Hz comparison panel so you can evaluate your display comprehensively in one place. For a complete system performance picture, combine this with our GPU test to ensure your graphics card is delivering the frames your monitor needs to perform at its best.
How to Use This UFO Test — Step by Step
- Step 1 — Set Frame Rate: Choose a FPS value that matches your monitor's advertised Hz. For a 144Hz monitor, select 144 FPS.
- Step 2 — Watch the UFO: Look at the UFO as it moves. Is it sharp and clear, or does it have a trailing shadow behind it?
- Step 3 — Try Different Backgrounds: Switch to grey or white backgrounds — ghosting is often more visible on lighter screens.
- Step 4 — Adjust Speed: A faster-moving object makes ghosting more visible. Start at speed 5 and try 8 for stress testing.
- Step 5 — Use Hz Compare Mode: See 30, 60, 144 and 240 FPS side by side to physically see the difference on your own monitor.
- Step 6 — Test Overdrive: Change your monitor's overdrive (response time) setting in its OSD menu, then re-run the test to see if ghosting improves or overshoot appears.
UFO Test Results — How to Read What You See
| What You See | What It Means | Cause | Recommended Fix |
|---|---|---|---|
| Sharp UFO, no trail at all | Excellent motion clarity | Fast panel + correct overdrive | No action needed — great result |
| Very faint single shadow | Mild ghosting — normal | Slight response time lag | Try raising overdrive one level in monitor OSD |
| Visible dark trail behind UFO | Moderate ghosting | Panel too slow for current speed | Increase overdrive, lower FPS cap, or upgrade panel |
| Long blurry smear behind UFO | Heavy ghosting | Very slow VA panel or no overdrive | Max out overdrive, or consider panel upgrade |
| Bright white halo ahead of UFO | Overdrive overshoot artifact | Overdrive set too high | Reduce overdrive by one step in monitor OSD menu |
| UFO appears choppy or jumping | Frame pacing issue or FPS below target | GPU dropping frames, VSync stutter, wrong Hz | Check display settings Hz, enable FreeSync/G-Sync |
| UFO looks smooth but blurry | Sample-and-hold persistence blur | Normal LCD behaviour — not ghosting | Enable strobe/BFI mode in monitor OSD if available |
60Hz vs 144Hz vs 240Hz vs 360Hz — What the UFO Test Shows
The difference between refresh rates is not just a number — it is a physical change in how long each frame stays on your screen. At 60Hz, each frame is displayed for 16.67 milliseconds before the next one arrives. Your eye tracks the moving UFO, but the image is not updating fast enough to keep up, creating a noticeable motion blur trail.
At 144Hz, each frame lasts only 6.94ms — less than half the time. The UFO appears dramatically sharper and more defined. At 240Hz (4.17ms) and 360Hz (2.78ms), motion becomes extremely fluid and the blur window shrinks further. Use the Hz Compare mode to see this difference directly on your own display. Keep in mind that reaching high frame rates consistently also depends on your CPU — use our CPU test to verify your processor is not bottlenecking your frame output at higher refresh rates.
| Refresh Rate | Frame Time | Pixel Hold Duration | Motion Clarity | Best Use Case |
|---|---|---|---|---|
| 60 Hz | 16.67 ms | 16.67 ms full | Moderate blur visible | Web browsing, video, casual gaming |
| 75 Hz | 13.33 ms | 13.33 ms full | Slightly improved | Budget gaming upgrade from 60Hz |
| 100 Hz | 10.00 ms | 10.00 ms full | Noticeably cleaner | General gaming, everyday use |
| 144 Hz | 6.94 ms | 6.94 ms full | Very sharp — big upgrade | Competitive gaming — most popular choice |
| 165 Hz | 6.06 ms | 6.06 ms full | Excellent | High-end 1440p gaming monitors |
| 240 Hz | 4.17 ms | 4.17 ms full | Near-perfect clarity | Esports, fast-paced FPS games |
| 360 Hz | 2.78 ms | 2.78 ms full | Elite — minimal blur | Professional esports tournaments |
What Is Monitor Ghosting?
Ghosting is the visible smear or dark shadow that trails behind fast-moving objects on your screen. It is caused by your monitor's pixels changing color too slowly — the previous frame's color bleeds into the current frame because the liquid crystal molecules have not fully realigned yet. This is measured in GtG (grey-to-grey) response time, typically expressed in milliseconds.
Ghosting is a monitor hardware problem — it is not caused by your GPU, game settings, network connection, or frame rate alone. If you see heavy ghosting at 60 FPS, you will see it at 144 FPS too if the panel is slow. The fix is either a better overdrive setting or a faster monitor panel. If you want to rule out GPU-related frame drops contributing to choppy motion, run our GPU test to confirm your graphics card is delivering stable, consistent frame output.
Ghosting vs Motion Blur — What Is the Difference?
These two terms are often confused but they are different problems with different causes and different fixes:
- Ghosting — caused by the pixel response time being too slow. The previous frame's color lingers. Visible as a dark or colored shadow. Fixed by better overdrive settings or a faster panel.
- Motion blur (sample-and-hold) — caused by pixels staying lit for the entire frame duration. Happens on all LCDs regardless of response time. Worse at lower Hz. Reduced by higher refresh rates or backlight strobing (BFI).
- Overdrive overshoot — caused by overdrive being set too high. Pixels overshoot their target color and briefly become too bright. Visible as a white or bright halo ahead of moving objects.
What Is Overdrive and How Do I Set It?
Overdrive (also called Response Time or AMA or Trace Free depending on the monitor brand) applies a higher voltage to LCD pixels to make them switch faster. This reduces ghosting. However, setting overdrive too high causes pixels to overshoot their target, creating bright artifacts in the direction of motion.
To find the right overdrive setting: open your monitor's OSD (on-screen display) menu → find the response time or overdrive setting → start at the middle option → run this UFO test at speed 7 or higher → if you see a dark ghost trail, go up one level → if you see a bright halo or inverse ghost, go down one level. The correct setting eliminates dark ghosting without introducing bright overshoot. For competitive gamers fine-tuning every millisecond of reaction time, also consider checking your APM test — actions-per-minute precision matters as much as display clarity in fast-paced play.
What Is Strobe / BFI and How Does It Help?
Backlight strobing (also called BFI — Black Frame Insertion — or ULMB on NVIDIA monitors) works by briefly turning off the backlight between each frame. This mimics how old CRT monitors worked — instead of pixels staying lit for the full 16ms between frames, the image flashes on and off, dramatically reducing perceived motion blur.
The downside of strobing is reduced brightness (typically 30–60% dimmer) and potential flicker perception. Our Strobe/BFI test mode simulates this effect using black frames so you can see how strobing improves motion clarity before enabling it on your monitor. If you play online games where reaction speed is everything, pairing strobe mode with a solid internet connection is equally important — use our ISP test to check that your network latency is not undermining the edge your display setup provides.
IPS vs TN vs VA vs OLED — Ghosting Comparison
| Panel Type | Typical GtG Response | Ghosting on UFO Test | Overdrive Need | Notes |
|---|---|---|---|---|
| TN (Twisted Nematic) | 0.5 – 2 ms | None to minimal | Low | Fastest pixels, poor colors and viewing angles. Still common in esports monitors. |
| IPS (In-Plane Switching) | 1 – 5 ms | Low to mild | Medium | Best balance of speed, color accuracy and viewing angles. Most popular gaming choice. |
| VA (Vertical Alignment) | 4 – 12 ms | Moderate to heavy | High | Excellent contrast ratio but slow dark-to-dark transitions cause noticeable smearing. |
| OLED (Organic LED) | 0.1 ms or less | Virtually none | None needed | Self-emissive pixels change near-instantly. Best motion clarity available today. |
| Mini-LED (IPS/VA backlit) | Same as base panel | Same as base panel | Same as base | Mini-LED improves contrast and HDR but does not change pixel response speed. |
How Accurate Is This Browser-Based UFO Test?
This tool uses requestAnimationFrame with a frame-accumulator timing system to deliver each UFO position update at the exact target frame rate interval, independent of your monitor's actual refresh rate. The accuracy is sufficient for visual evaluation of ghosting and motion clarity.
However, for sub-millisecond frame pacing accuracy (testing for micro-stutter at the 0.1ms level), native software tools like NVIDIA FCAT VR, CapFrameX or Blur Busters' native test are more precise. For practical display evaluation — which is what this tool is designed for — browser accuracy is fully adequate. To get the most out of this test, ensure your entire system is performing optimally: run our CPU test to confirm your processor is not throttling under gaming load, and use our FPS test to measure the actual frames your system is delivering to your display in real time.
Frequently Asked Questions — UFO Monitor Test
There are three common reasons. First, your monitor may not actually be running at 144Hz — check Windows Settings → System → Display → Advanced Display Settings and confirm the refresh rate shown. Second, even at 144Hz, sample-and-hold motion blur still exists because LCD pixels stay lit for the full 6.94ms between frames — this is normal and different from ghosting. Third, you may have a cable limitation: HDMI 1.4 cables cap many monitors at 60Hz. Switch to a DisplayPort cable or HDMI 2.0/2.1 for full 144Hz speed. If blur persists after addressing all three, use our FPS test to verify your system is actually rendering enough frames to take advantage of your monitor's full refresh rate.
testufo.com (created by Blur Busters) is the original UFO motion test and a reference standard in the community. Our tool is independently built and adds several additional features including a real-time ghosting meter, strobe/BFI simulation mode, crosstalk test, pixel persistence visualization, and an integrated Hz detection system that tells you your actual monitor refresh rate. Both tools serve the same core purpose of visual motion evaluation, and both are reliable for practical display testing.
G-Sync and FreeSync do not directly reduce ghosting from slow pixel response times. What they do is eliminate screen tearing and reduce VSync stutter by matching your monitor's refresh rate to your GPU's output frame rate. This can make motion feel smoother and more consistent, which reduces the perception of ghosting by removing frame pacing irregularities. But if your panel has a slow GtG response time, G-Sync will not change that — you will still see trailing artifacts on this UFO test at high speeds.
Set the UFO test speed to 7 or 8 and use a grey background (most revealing for ghosting). Run the test with your current overdrive setting. If you see a dark shadow trailing behind the UFO, your overdrive is too low — increase it one step in your monitor's OSD menu. If you see a bright white or inverse-colored halo ahead of the UFO, overdrive is too high — reduce it one step. The ideal overdrive setting shows a sharp, clean UFO with no trailing shadow and no forward halo. Repeat this test whenever you change your game's resolution or FPS cap, as the optimal overdrive can vary. If choppy motion persists even after correcting overdrive, use our CPU test to check whether processor bottlenecking is causing inconsistent frame delivery.
Frame pacing is how consistently spaced your frames are over time. Even if your average FPS is 144, if some frames arrive after 3ms and others after 12ms, motion will look uneven and stuttery — like the UFO is jumping rather than gliding smoothly. This tool uses a frame-accumulator system to deliver each UFO position update at a precise interval, so any irregularity you see in the UFO's movement reflects your system's frame pacing, not the test itself. Consistent, smooth UFO movement indicates good frame pacing. Jumpy, uneven motion suggests GPU load spikes, driver issues, or VSync timing problems. For esports players, frame pacing issues can directly hurt mechanical precision — tracking your APM test results alongside this test can reveal whether stuttery visuals are affecting your input consistency during high-intensity play.
Strobe mode (ULMB, ELMB, 1ms Motion Blur Reduction, etc.) dramatically reduces motion blur and makes fast movement look extremely sharp. However, it comes with trade-offs: brightness drops by 30–60%, it usually cannot be used alongside VRR (G-Sync/FreeSync), and some people find the flicker perceptible or uncomfortable. It is most useful for competitive FPS games where motion clarity is critical. Use our Strobe/BFI simulation mode to see the visual effect before enabling it on your monitor. If the result looks better to you and you do not notice the flicker, it is worth trying on your actual monitor. For online competitive play, also confirm your connection is not adding latency on top — our ISP test will show you whether your network speed and ping are competitive-ready.
The test works in all modern browsers but Chrome and Edge typically give the most consistent results because they have the most mature hardware acceleration support for canvas animations. Firefox works correctly but may show slightly different frame timing behaviour. Safari on Mac also works reliably. For best results, enable hardware acceleration in your browser settings, close unnecessary tabs, and avoid running heavy background applications during the test. The test requires an active internet connection to load fonts but runs entirely offline after the initial page load.