Comparison
GT3900UHD vs ZK431ST-B
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A side-by-side look at how the Optoma GT3900UHD and Optoma ZK431ST-B compare on specs, accuracy, room requirements, and price. No hype — just the parts of the decision a buyer actually weighs.
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Prices confirmed Nov 10, 2026 · we check every retailer daily
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Full specificationsEvery spec for both, line by line
Specifications
The numbers, lined up.
Image
| Spec | GT3900UHD | ZK431ST-B |
|---|---|---|
| Resolution | 4K UHD (3840×2160) | 4K UHD (3840×2160); Optoma calls it True 4K UHD and names no chip |
| Lumens | 4,000 (ISO 21118) | 4,100 (ISO 21118) |
| HDR | HDR10, HLG | — |
| Picture Mode | Golf Mode | Golf Sim colour mode (preset) |
| Screen Size | 30–150 in (Optoma's page and datasheet) | 36–300 in (Optoma's spec table says 30–300, its feature list 36–300; the narrower range is used) |
- ResolutionGT3900UHD4K UHD (3840×2160)ZK431ST-B4K UHD (3840×2160); Optoma calls it True 4K UHD and names no chip
- LumensGT3900UHD4,000 (ISO 21118)ZK431ST-B4,100 (ISO 21118)
- HDRGT3900UHDHDR10, HLGZK431ST-B—
- Picture ModeGT3900UHDGolf ModeZK431ST-BGolf Sim colour mode (preset)
- Screen SizeGT3900UHD30–150 in (Optoma's page and datasheet)ZK431ST-B36–300 in (Optoma's spec table says 30–300, its feature list 36–300; the narrower range is used)
Hardware
| Spec | GT3900UHD | ZK431ST-B |
|---|---|---|
| Light Source | DuraCore laser (30,000 hours, eco) | DuraCore laser (30,000 hours, eco) |
| Throw Ratio | 0.496:1 (fixed) | 0.496:1 (short throw, fixed) |
| Offset | 114% (±5%); no lens shift | — |
| Dimensions | 10.8 × 8.5 × 4.5 in (W × D × H, datasheet) | — |
| Lens | — | Fixed 0.496:1 short-throw lens (no zoom, no lens shift) |
| Keystone | — | ±15° with Smart Fit auto-alignment |
- Light SourceGT3900UHDDuraCore laser (30,000 hours, eco)ZK431ST-BDuraCore laser (30,000 hours, eco)
- Throw RatioGT3900UHD0.496:1 (fixed)ZK431ST-B0.496:1 (short throw, fixed)
- OffsetGT3900UHD114% (±5%); no lens shiftZK431ST-B—
- DimensionsGT3900UHD10.8 × 8.5 × 4.5 in (W × D × H, datasheet)ZK431ST-B—
- LensGT3900UHD—ZK431ST-BFixed 0.496:1 short-throw lens (no zoom, no lens shift)
- KeystoneGT3900UHD—ZK431ST-B±15° with Smart Fit auto-alignment
Requirements
| Spec | GT3900UHD | ZK431ST-B |
|---|---|---|
| Throw Distance | 100 in at about 3.6 ft (Optoma's manual) | — |
- Throw DistanceGT3900UHD100 in at about 3.6 ft (Optoma's manual)ZK431ST-B—
Performance
| Spec | GT3900UHD | ZK431ST-B |
|---|---|---|
| Input Lag | As low as 4.3 ms at 1080p/240Hz (Optoma) | 16.8 ms at 4K/60Hz and 8.6 ms at 1080p/120Hz with Enhanced Gaming on (Optoma's page says 16.7 ms at 4K/60; the manual's 16.8 is used); 33.5 ms at 4K/60 with it off. Keystone and four-corner correction are disabled in low-latency mode |
- Input LagGT3900UHDAs low as 4.3 ms at 1080p/240Hz (Optoma)ZK431ST-B16.8 ms at 4K/60Hz and 8.6 ms at 1080p/120Hz with Enhanced Gaming on (Optoma's page says 16.7 ms at 4K/60; the manual's 16.8 is used); 33.5 ms at 4K/60 with it off. Keystone and four-corner correction are disabled in low-latency mode
Room planner
See each one in your sim room.
The planner draws each unit to scale with your room and your swing: where it mounts, the throw it needs, and whether your shadow crosses the light. Put in your room once, then switch units in the planner to compare.
Persona fitWho each one is better for
Who each one is better for
Both fit the same buyers.
Neither one wins a persona the other doesn’t. The choice comes down to specs, price, and room fit rather than buyer profile.
Both fit
- Space-Constrained
- Family Setup
- Performance Seeker
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