Between the Phone (3a) and OnePlus Open 2, the Phone (3a) comes out ahead in weight, while the OnePlus Open 2 wins on antutu and ram. Overall, the Phone (3a) scores 62.5 and the OnePlus Open 2 scores 74.5 on our Mars Score.
Which should you buy?
The OnePlus Open 2 is the clear pick on raw spec strength, leading by 12.0 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the Phone (3a) if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are weight.
Pick the OnePlus Open 2 if you push the hardware — gaming, on-device AI, heavy multitasking — and the extra compute headroom is worth the trade-offs. Its strongest claims are antutu, ram, wired charging, among others.
Both ship with comparable main camera, refresh rate, 5g support, so those specs don't separate the two — focus on the differences below.
Bottom line: the OnePlus Open 2 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Nothing - Phone (3a) wins
- ▲Weight — 38.00 g less. 201 vs 239.
Why OnePlus Open 2 wins
- ▲AnTuTu — 226.83% more. 2680000 vs 820000.
- ▲RAM — 100.00% more. 16 GB vs 8 GB.
- ▲Wired charging — 60.00% more. 80 W vs 50 W.
- ▲Screen size — 18.17% more. 8.0 " vs 6.77 ".
- ▲Battery capacity — 14.00% more. 5700 mAh vs 5000 mAh.
- ▲Pixel density — 3.88% more. 402 ppi vs 387 ppi.
- ▲Water resistance: IP68 (vs IP64).
- ▲Promised OS updates: 4 (vs 3).
Spec comparison
Design
| Spec | Nothing - Phone (3a) | OnePlus Open 2 |
|---|---|---|
| Weight | 201 glead | 239 g |
| Thickness | 8.4 mmlead | 11.7 mm |
| Water resistanceⓘ | IP64 | IP68lead |
| Form factor | bar | foldable_booklead |
Display
| Spec | Nothing - Phone (3a) | OnePlus Open 2 |
|---|---|---|
| Screen sizeⓘ | 6.77 " | 8.0 "lead |
| Pixel densityⓘ | 387 ppi | 402 ppilead |
| Refresh rateⓘ | 120 Hz | 120 Hz |
| Peak brightnessⓘ | 3000 nits | 4500 nitslead |
Performance
Cameras
| Spec | Nothing - Phone (3a) | OnePlus Open 2 |
|---|---|---|
| Main cameraⓘ | 50 MP | 50 MP |
| Front camera | 32 MP | 32 MP |
| Optical image stabilizationⓘ | true | true |
Battery
| Spec | Nothing - Phone (3a) | OnePlus Open 2 |
|---|---|---|
| Battery capacity | 5000 mAh | 5700 mAhlead |
| Wired chargingⓘ | 50 W | 80 Wlead |
| Wireless chargingⓘ | 0 W | 50 Wlead |
Connectivity
| Spec | Nothing - Phone (3a) | OnePlus Open 2 |
|---|---|---|
| 5G supportⓘ | true | true |
| Headphone jack | false | false |
| microSD slot | false | false |
Operating System
| Spec | Nothing - Phone (3a) | OnePlus Open 2 |
|---|---|---|
| OS | Android | Android |
| Promised OS updates | 3 years | 4 yearslead |
Frequently asked
Which has better battery, Phone (3a) or OnePlus Open 2?+
OnePlus Open 2 has 14.0% more battery — 5000 mAh vs 5700 mAh.
Which is lighter, Phone (3a) or OnePlus Open 2?+
Phone (3a) is 38g lighter — 201g vs 239g.
Is Phone (3a) waterproof?+
Phone (3a) has an IP64 rating.
Does OnePlus Open 2 support 5G?+
Yes, OnePlus Open 2 supports 5G.
Which has more RAM, Phone (3a) or OnePlus Open 2?+
OnePlus Open 2 offers 16GB of RAM.
Which has a better camera, Phone (3a) or OnePlus Open 2?+
OnePlus Open 2 has a 50 MP main camera vs 50 MP.
Spec-level deep dives
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