The Optoma ZK431ST-B is brighter (4,100 lumens against 3,200). The Optoma ZK431ST-B throws a given image from closer (ratio 0.496 against 0.9). The Optoma ZK431ST-B uses a laser light source; the other uses a lamp. The Optoma ZK431ST-B costs $400 less at the prices we observed.
Side by side
| Specification | BenQ TK710STi | Optoma ZK431ST-B |
|---|---|---|
| Brightness | 3,200 lm | 4,100 lm |
| Resolution | 4K UHD (3840 × 2160) | 4K UHD (3840 × 2160) |
| Native aspect | 16:9 | 16:9 |
| Throw ratio | 0.9–1.08:1 | 0.496:1 |
| Distance for a 10.5 × 8 ft 4:3 screen | 12′ 7″ | 6′ 11″ |
| Brightness on that screen | 29 fL | 37 fL |
| Light source | Lamp | Laser |
| Rated life | 15,000 h | 30,000 h |
| Zoom | 1.2× | Fixed |
| Lens shift | — | — |
| Input lag | About 17 ms (1080p game mode) | 16.7 ms (4K 60 Hz); 8.6 ms (1080p 120 Hz) |
| Price seen | $2,199 | $1,799 |
Highlighted rows differ. Figures come from each product's sources; room depth, distances and brightness are FOREference calculations using the same method for both.
Which should you choose?
BenQ TK710STi
Choose the BenQ TK710STi if you prefer its maker, seller or ecosystem — the published figures do not favour it.
Optoma ZK431ST-B
Choose the Optoma ZK431ST-B if your room has ambient light or a large screen or you need to mount it close to the screen.
Before you buy either
- Check the room: room size calculator and ceiling height calculator.
- Confirm what each seller includes — accessories, software trials and bundles change often.
- Read the limitations on each full reference page.
FOREference compares published specifications; we have not tested these products side by side. How we work · Disclosure