Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| Wireless charging | 50 W | 15 W |
| Refresh rate | 120 Hz | 185 Hz |
| Wired charging | 80 W | 65 W |
| Screen size | 8.0 " | 6.78 " |
| Weight | 239 g | 227 g |
| AnTuTu | 2680000 | 2580000 |
Between the OnePlus Open 2 and ROG Phone 9, the OnePlus Open 2 comes out ahead in wireless charging / wired charging, while the ROG Phone 9 wins on refresh rate / weight. Overall, the OnePlus Open 2 scores 71.8 and the ROG Phone 9 scores 72.4 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (71.8 vs 72.4). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
Pick the OnePlus Open 2 if the display is what you stare at all day — refresh rate, brightness, or sharpness is where the difference will be most visible. The biggest gaps in its favor are wireless charging, wired charging, screen size, among others. The single most decisive one: Wireless charging — 233.33% more. 50 W vs 15 W.
Pick the ROG Phone 9 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. Its strongest claims are refresh rate, weight, battery capacity, among others. The single most decisive one: Refresh rate — 54.17% more. 185 Hz vs 120 Hz.
Both ship with comparable ram, main camera, 5g support, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: OnePlus Open 2 or ASUS - ROG Phone 9?
ASUS - ROG Phone 9 leads the current Mars Score by 0.6 points.The more useful decision is the trade-off behind that result: compare screen size, pixel density, battery capacity against the way you will actually use the product.
Choose OnePlus Open 2 if…
OnePlus Open 2 has the measurable edge on wireless charging w, wired charging w, screen size in.
Choose ASUS - ROG Phone 9 if…
ASUS - ROG Phone 9 has the measurable edge on refresh rate hz, weight g, battery capacity mah.
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 OnePlus Open 2 wins
- ▲Wireless charging — 233.33% more. 50 W vs 15 W.
- ▲Wired charging — 23.08% more. 80 W vs 65 W.
- ▲Screen size — 17.99% more. 8.0 " vs 6.78 ".
- ▲AnTuTu — 3.88% more. 2680000 vs 2580000.
- ▲Pixel density — 3.61% more. 402 ppi vs 388 ppi.
- ▲Promised OS updates: 4 (vs 3).
Why ASUS - ROG Phone 9 wins
- ▲Refresh rate — 54.17% more. 185 Hz vs 120 Hz.
- ▲Weight — 12.00 g less. 227 vs 239.
- ▲Battery capacity — 1.75% more. 5800 mAh vs 5700 mAh.
- ▲Has Headphone jack.
Spec comparison
Design
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| Weight | 239 g | 227 glead |
| Thickness | 11.7 mm | 8.9 mmlead |
| Water resistanceⓘ | IP68 | IP68 |
| Form factor | foldable_booklead | bar |
Display
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| Screen size | 8.0 "lead | 6.78 " |
| Pixel densityⓘ | 402 ppilead | 388 ppi |
| Refresh rateⓘ | 120 Hz | 185 Hzlead |
| Peak brightnessⓘ | 4500 nitslead | 2500 nits |
Performance
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| RAMⓘ | 16 GB | 16 GB |
| Storageⓘ | 512 GB | 512 GB |
| AnTuTuⓘ | 2680000lead | 2580000 |
| CPU total clockⓘ | 22.8 GHzlead | 22.0 GHz |
Cameras
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| Main cameraⓘ | 50 MP | 50 MP |
| Front camera | 32 MP | 32 MP |
| Optical image stabilizationⓘ | true | true |
Battery
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| Battery capacityⓘ | 5700 mAh | 5800 mAhlead |
| Wired chargingⓘ | 80 Wlead | 65 W |
| Wireless chargingⓘ | 50 Wlead | 15 W |
Connectivity
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| 5G supportⓘ | true | true |
| Headphone jack | false | truelead |
| microSD slot | false | false |
Operating System
| Spec | OnePlus Open 2 | ASUS - ROG Phone 9 |
|---|---|---|
| OS | Android | Android |
| Promised OS updates | 4 yearslead | 3 years |
Frequently asked
Which has better battery, OnePlus Open 2 or ROG Phone 9?+
ROG Phone 9 has 1.8% more battery — 5700 mAh vs 5800 mAh.
Which is lighter, OnePlus Open 2 or ROG Phone 9?+
ROG Phone 9 is 12g lighter — 239g vs 227g.
Is OnePlus Open 2 waterproof?+
OnePlus Open 2 has an IP68 rating.
Does ROG Phone 9 support 5G?+
Yes, ROG Phone 9 supports 5G.
Which has a better camera, OnePlus Open 2 or ROG Phone 9?+
ROG Phone 9 has a 50 MP main camera vs 50 MP.