Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Dreame - X40 Ultra | Roborock - S9 MaxV Ultra |
|---|---|---|
| Suction | 12000 Pa | 22000 Pa |
| Battery life | 210 min | 180 min |
| Water tank | 270 ml | 300 ml |
Between the X40 Ultra and S9 MaxV Ultra, the X40 Ultra comes out ahead in battery life, while the S9 MaxV Ultra wins on suction / water tank. Overall, the X40 Ultra scores 83.9 and the S9 MaxV Ultra scores 88 on our Mars Score.
Which should you buy?
The S9 MaxV Ultra edges ahead on the Mars Score (83.9 vs 88), but the 4.1-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the X40 Ultra if you care most about battery life. The biggest gaps in its favor are battery life. The single most decisive one: Battery life — 16.67% more. 210 min vs 180 min.
Pick the S9 MaxV Ultra if you care most about suction / water tank. Its strongest claims are suction, water tank. The single most decisive one: Suction — 83.33% more. 22000 Pa vs 12000 Pa.
Both ship with comparable mopping, lidar, self-empty base, 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: Dreame - X40 Ultra or Roborock - S9 MaxV Ultra?
Roborock - S9 MaxV Ultra leads the current Mars Score by 4.1 points.The more useful decision is the trade-off behind that result: compare suction, battery life against the way you will actually use the product.
Choose Dreame - X40 Ultra if…
Dreame - X40 Ultra has the measurable edge on battery life min.
Choose Roborock - S9 MaxV Ultra if…
Roborock - S9 MaxV Ultra has the measurable edge on suction pa, water tank capacity ml.
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 Dreame - X40 Ultra wins
- ▲Battery life — 16.67% more. 210 min vs 180 min.
Why Roborock - S9 MaxV Ultra wins
- ▲Suction — 83.33% more. 22000 Pa vs 12000 Pa.
- ▲Water tank — 11.11% more. 300 ml vs 270 ml.
Spec comparison
Cleaning
| Spec | Dreame - X40 Ultra | Roborock - S9 MaxV Ultra |
|---|---|---|
| Suction | 12000 Pa | 22000 Palead |
| Mopping | true | true |
| Water tank | 270 ml | 300 mllead |
| Dustbin | 350 ml | 350 ml |
| Carpet detection | true | true |
Navigation
| Spec | Dreame - X40 Ultra | Roborock - S9 MaxV Ultra |
|---|---|---|
| Lidar | true | true |
| Camera navigation | true | true |
| AI obstacle avoidance | true | true |
| Max climb | 60 mmlead | 40 mm |
Autonomy
| Spec | Dreame - X40 Ultra | Roborock - S9 MaxV Ultra |
|---|---|---|
| Battery life | 210 minlead | 180 min |
| Self-empty base | true | true |
| Self-wash mop | true | true |
| Self-dry mop | true | true |
| Noise | 65 dB | 65 dB |
Frequently asked
Which has stronger suction, X40 Ultra or S9 MaxV Ultra?+
S9 MaxV Ultra delivers 22000 Pa vs 12000 Pa.
Do X40 Ultra or S9 MaxV Ultra mop?+
Both can mop.
Which has a self-emptying base, X40 Ultra or S9 MaxV Ultra?+
Both ship with a self-emptying base.