What you’ll learn (quick overview)
You’ll learn what the UFO test is, how to run it step-by-step, how to read ghosting trails, how FPS and Hz change motion clarity, and how to fix common issues such as overshoot, frame skipping, and stutter/tearing. We’ll also cover VRR (G-SYNC/FreeSync) tuning, MPRT vs GtG, and when to enable backlight strobing.
Plus, you’ll see how panel types (IPS, VA, OLED) differ in motion behavior, how to spot color ghosting from certain backlights, and when to use variable overdrive with VRR. We’ll share a simple method to validate frame delivery with photos, a quick FPS-cap strategy for smoother gameplay, and a practical checklist to lock in your final settings.
What is the UFO test?
The UFO test (often called moving UFO test or monitor UFO test) is a browser-based motion test that scrolls a small UFO sprite at a fixed speed across your screen. It’s designed to make motion artifacts easy to see—ghosting, inverse ghosting (overshoot/coronas), blur, tearing, and stutter—so you can dial in monitor settings for the clearest motion. The most widely used suite is Blur Busters’ TestUFO with dedicated pages for ghosting, frame skipping, MPRT vs GtG, and more.
Why the UFO test works
Fast panning at a standardized speed (Blur Busters commonly uses ~960 pixels/second) makes trails and softness obvious, letting you compare settings, refresh rates, and overdrive levels quickly and visually.
Key terms you’ll see in a UFO test
- Ghosting (smearing): dark trails behind the UFO from slow response times.
- Inverse ghosting (coronas/overshoot): bright/halo trails from too-strong overdrive.
- MPRT vs GtG: GtG = pixel transition speed; MPRT = how long a frame is visible (sample-and-hold blur). MPRT controls perceived motion blur far more than tiny GtG differences.
- VRR (G-SYNC/FreeSync): matches refresh to game FPS to cut tearing and stutter; proper setup matters.
How to run the UFO test correctly (step-by-step)
- Use the right page
Open the official Ghosting / Pursuit Camera page to assess trails; use Multiple Framerates and GtG vs MPRT pages to compare blur across Hz/FPS and visibility time. - Full-screen at 100% zoom
Set browser zoom to 100%, full-screen the tab, and keep it on the primary display. - Lock in refresh rate
In OS > Display settings and GPU control panel, select the monitor’s maximum Hz (e.g., 144/240/360 Hz). - Disable funky processing
Turn off motion smoothing/interpolation on TVs, “dynamic contrast,” and any blur filters. Keep HDR off for testing unless you’re verifying HDR behavior. - Stabilize frame delivery
Close heavy background apps. If testing games, cap FPS and align it with Hz (e.g., 141 FPS on 144 Hz) to reduce spikes. For browsers, just leave the test page alone. - Observe the UFO trails
Look for faint dark trails (underdrive), bright halos (overshoot), or double images. Adjust overdrive (OD/TraceFree/Response Time) until the trail is minimal and balanced. - Optional: photograph results
To check frame skipping, use the dedicated Frame Skipping Checker, and photograph the grid with a long exposure as instructed. Missing boxes = dropped refreshes.
Reading results: what different trails mean (with fixes)
1) Soft blur with no distinct trail
Interpretation: GtG is fast enough; blur is mostly MPRT (sample-and-hold). Higher refresh rate or strobing reduces it.
Fixes:
- Raise Hz (120 → 144 → 240 → 360).
- Enable strobing/ULMB modes if offered (note: may add crosstalk).
- Maintain stable FPS equal to or near Hz.
2) Dark trail behind the UFO (ghosting)
Interpretation: response time too slow (often VA dark-level transitions).
Fixes:
- Increase overdrive one step.
- Use a higher refresh rate.
- If VA smearing persists, try different color/contrast or consider a model with faster transitions (e.g., IPS or OLED).
3) Bright/halo trail (inverse ghosting/coronas)
Interpretation: overdrive overshoot is too aggressive.
Fixes:
- Lower overdrive a notch.
- With VRR, use “variable overdrive” if available.
4) Colored trails (red/green tints)
Interpretation: color/phosphor asymmetry (e.g., KSF red phosphor backlights) or mini-LED local dimming interaction. Use the Color Ghosting Test to confirm.
Fixes:
- Pick a different overdrive level.
- If persistent, it’s panel/backlight behavior—evaluate another model.
5) Micro-stutters or tearing during the test
Interpretation: frame pacing or sync issue.
Fixes:
- With VRR monitors, enable G-SYNC (NVIDIA) or FreeSync (AMD) in the GPU panel and the monitor OSD. For NVIDIA, verify Set up G-SYNC is enabled for fullscreen (or windowed + fullscreen), then cap FPS just below max Hz to avoid hitting the V-SYNC ceiling.
- Without VRR, use a consistent FPS cap that evenly divides your refresh rate.
6) Missing boxes in the frame-skipping photo
Interpretation: the display isn’t presenting every refresh (common with overclocks or unusual timings).
Fixes:
- Drop to the previous stable refresh rate or use validated timings; re-test with the Frame Skipping Checker.
UFO test FPS vs monitor Hz: what actually matters
- Match or track FPS to Hz. 144 FPS on 144 Hz reduces blur versus 90 FPS on 144 Hz because MPRT depends on frame visibility time per refresh.
- VRR smooths fluctuations. G-SYNC/FreeSync adjust display refresh dynamically to FPS, reducing tearing and stutter when frame times vary. Properly configured VRR is ideal for real games; the UFO test simply helps you spot motion artifacts quickly.
- Higher Hz = lower MPRT. Going from 60 → 120 → 240 Hz progressively shortens each frame’s persistence, reducing perceived blur even when GtG is already “1 ms.”
MPRT vs GtG (the reason 240/360 Hz feels so much clearer)
GtG is the transition time between gray levels; MPRT is the time each frame is held on screen. For sample-and-hold displays (LCD and OLED), perceived motion blur scales mostly with MPRT. That’s why, even on “1 ms” panels, jumping from 144 to 240 Hz produces a visible clarity bump during a moving UFO test. Strobing artificially lowers MPRT further by flashing the backlight briefly each refresh (trade-offs: brightness loss and possible double-image crosstalk).
Choosing the right overdrive setting (and why “Strong” isn’t always best)
Many monitors ship with several overdrive presets. The “Strong” preset often overshoots, causing inverse ghosting halos around the UFO; the “Weak” preset can leave slow smearing. Your goal is the cleanest UFO with the faintest, shortest trail. Independent labs (e.g., RTINGS) demonstrate how too-aggressive OD creates visible halos and recommend stepping down for balance—especially at lower frame rates or with VRR enabled.
Verifying VRR and eliminating tearing/stutter
- Enable VRR in GPU software (NVIDIA “Set up G-SYNC”; AMD “Adaptive Sync/FreeSync”). Confirm the monitor OSD shows VRR “On.”
- Cap FPS ~2–3 below max Hz (e.g., 237 on 240 Hz) to avoid V-SYNC behavior at the limit and keep latency low while staying tear-free inside the VRR window. Blur Busters’ G-SYNC testing discusses this cap strategy.
- Use certified hardware when possible. VESA’s Adaptive-Sync Display CTS defines rigorous performance tests for VRR quality; look for certified models or recent updates (v1.1/1.1a).
The “moving UFO test” checklist (quick wins)
- Test at native resolution and maximum Hz.
- Use Full-screen, 100% zoom.
- Start with medium overdrive; adjust to remove halos or smearing.
- If you see colored trails, confirm with Color Ghosting Test.
- Photograph Frame Skipping Checker to validate overclocks/timings.
- For real games: enable G-SYNC/FreeSync and set a near-Hz FPS cap.
Case study: why a 240 Hz OLED looks so sharp in the UFO test
- Fast transitions: OLED sub-millisecond GtG reduces dark smearing.
- High refresh: 240 Hz (or higher) cuts frame visibility time, lowering MPRT blur.
- Balanced OD: OLEDs don’t need heavy overdrive, so overshoot halos are rare.
Independent motion tests repeatedly show lower overshoot on OLED vs many LCDs while noting that the highest OD settings on LCDs can create distracting coronas during the moving UFO test.
Troubleshooting: common UFO test problems (and fixes)
- The UFO looks double at low FPS: your FPS is far below Hz; raise FPS, drop settings, or lower refresh to maintain a tighter FPS↔Hz ratio.
- The UFO jitters every few seconds: background apps or inconsistent frame pacing—close overlays, recorders, and browser extensions; try another browser. For deeper checks, use the VSYNC Animation Timing Graph to spot skipped frames.
- The grid shows missing boxes: back off your overclock/CRU timings; re-test with the frame skipping page and long-exposure photo.
- You enabled VRR but still see tearing: confirm G-SYNC/FreeSync is enabled in both GPU panel and monitor OSD, and add a small FPS cap below max Hz.
Advanced tips for power users
- Pursuit camera testing: Advanced reviewers use a slow camera panning technique to photograph the moving UFO and compare trails precisely (the TestUFO ghosting page references pursuit-style evaluation). If you’re documenting results, keep shutter speed consistent across shots.
- Test multiple speeds: Some artifacts appear at higher motion speeds; try 480, 960, and 1920 px/s where available.
- Check variable overdrive: Many VRR monitors change OD with refresh; verify UFO trails at 60, 120, and max Hz.
- Know your limits: VESA’s Adaptive-Sync program sets thresholds for flicker, overshoot, and low-framerate behavior. Hardware that passes tends to behave better across the UFO test range.
FAQs
Is the UFO test accurate for all monitors?
It’s excellent for visual artifact detection (ghosting/overshoot/tearing) and quick comparisons. For lab-grade numbers, consult independent measurements (e.g., RTINGS) and VESA certification details.
Does 1 ms GtG mean no blur?
No. MPRT dominates perceived blur; higher refresh rate or strobing reduces it more than tiny GtG differences.
Why do games look blurrier than the UFO test?
Games have varying FPS, camera speeds, post-processing, and frame pacing. Use VRR and an FPS cap, then tune overdrive as you did on the moving UFO test.
How do I verify my overclocked Hz is real?
Run the Frame Skipping page and take the required long-exposure photo; missing boxes mean it’s not stable.
Conclusion
The UFO test is the quickest way to make motion artifacts visible and fixable. In one glance, you can spot blur (MPRT), ghosting (slow transitions), inverse ghosting (overshoot), tearing, stutter, and even frame skipping. Use it to translate what your eyes feel into clear, repeatable tweaks.
Your 60-second action plan
- Set your display to max refresh rate, open the moving UFO test full-screen at 100% zoom.
- Start with medium overdrive; nudge up if you see dark smearing, nudge down if you see bright halos.
- If you game, enable VRR (G-SYNC/FreeSync) and cap FPS 2–3 below max Hz for smooth, tear-free motion.
- Validate stability with the Frame Skipping check (long-exposure photo as instructed).
- Re-run at multiple speeds (e.g., 480–960–1920 px/s) to confirm your settings hold up.
Already tried it? Share your setup in the comments—monitor model, refresh rate, overdrive level, VRR on/off, and your FPS cap. Did overdrive tuning clean up trails more, or did a smart VRR + FPS cap deliver the biggest win for you? If you hit a snag (colored trails, micro-stutter, or skipped frames), drop a note and we’ll help you troubleshoot.
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