Between the X40 Ultra and Roomba j9+, the X40 Ultra comes out ahead in battery life and noise, while the Roomba j9+ wins on several specs. Overall, the X40 Ultra scores 70.7 and the Roomba j9+ scores 49.8 on our Mars Score.
Which should you buy?
The X40 Ultra is the clear pick on raw spec strength, leading by 20.9 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 X40 Ultra if you care most about battery life and noise. The biggest gaps in its favor are battery life, noise, mopping, among others.
The Roomba j9+ similarly doesn't carry a headline advantage on the popular specs — look at the full table for category-specific deltas.
Both ship with comparable self-empty base, ai obstacle avoidance, so those specs don't separate the two — focus on the differences below.
Bottom line: the X40 Ultra is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Dreame - X40 Ultra wins
- ▲Battery life — 5.00% more. 210 min vs 200 min.
- ▲Noise — 3.00 dB less. 65 vs 68.
- ▲Has Mopping.
- ▲Has Lidar.
- ▲Suction: 12000 Pa vs 0 Pa.
- ▲Water tank: 270 ml vs 0 ml.
Why iRobot - Roomba j9+ wins
- No decisive advantages.
Spec comparison
Cleaning
| Spec | Dreame - X40 Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Suction | 12000 Palead | 0 Pa |
| Mopping | truelead | false |
| Water tank | 270 mllead | 0 ml |
| Dustbin | 350 ml | 500 mllead |
| Carpet detection | true | true |
Navigation
| Spec | Dreame - X40 Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Lidar | truelead | false |
| Camera navigation | true | true |
| AI obstacle avoidance | true | true |
| Max climb | 60 mmlead | 20 mm |
Autonomy
| Spec | Dreame - X40 Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Battery life | 210 minlead | 200 min |
| Self-empty base | true | true |
| Self-wash mop | truelead | false |
| Self-dry mop | truelead | false |
| Noise | 65 dBlead | 68 dB |
Frequently asked
Which has stronger suction, X40 Ultra or Roomba j9+?+
X40 Ultra delivers 12000 Pa vs 0 Pa.
Do X40 Ultra or Roomba j9+ mop?+
X40 Ultra mops; Roomba j9+ vacuums only.
Which has a self-emptying base, X40 Ultra or Roomba j9+?+
Both ship with a self-emptying base.
Spec-level deep dives
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