Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Optoma - UHD35STx | ViewSonic - X2-4K |
|---|---|---|
| Brightness | 3600 lm | 2900 lm |
| Light source | Lamp | Laser |
Between the UHD35STx and X2-4K, the UHD35STx comes out ahead in brightness, while the X2-4K wins on light source. Overall, the UHD35STx scores 78.9 and the X2-4K scores 73.5 on our Mars Score.
Which should you buy?
The UHD35STx edges ahead on the Mars Score (78.9 vs 73.5), but the 5.4-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the UHD35STx if you care most about brightness. The biggest gaps in its favor are brightness. The single most decisive one: Brightness — 24.14% more. 3600 lm vs 2900 lm.
Pick the X2-4K if you care most about light source. Its strongest claims are light source. The single most decisive one: Light source: Laser (vs Lamp).
Both ship with comparable resolution, short-throw, so those specs do not separate the two — focus on the differences below.
Bottom line: the UHD35STx is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Optoma - UHD35STx or ViewSonic - X2-4K?
Optoma - UHD35STx leads the current Mars Score by 5.4 points.The more useful decision is the trade-off behind that result: compare brightness, light source against the way you will actually use the product.
Choose Optoma - UHD35STx if…
Optoma - UHD35STx has the measurable edge on brightness lumens.
Choose ViewSonic - X2-4K if…
ViewSonic - X2-4K has the measurable edge on light source.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Optoma - UHD35STx wins
- ▲Brightness — 24.14% more. 3600 lm vs 2900 lm.
Why ViewSonic - X2-4K wins
- ▲Light source: Laser (vs Lamp).
Spec comparison
Image
| Spec | Optoma - UHD35STx | ViewSonic - X2-4K |
|---|---|---|
| Resolutionⓘ | 4K | 4K |
| Brightnessⓘ | 3600 lmlead | 2900 lm |
| Contrast | 1000000:1 | 3000000:1 |
| Light source | Lamp | Laserlead |
| Short-throw | true | true |
Smart & Connectivity
| Spec | Optoma - UHD35STx | ViewSonic - X2-4K |
|---|---|---|
| Smart OS | None | Google TV |
| HDMI inputs | 2 | 2 |
| Built-in speakers | true | true |