Pet hair is the single hardest debris type for a robotic vacuum to deal with — it tangles around brush rollers, escapes side brushes, and embeds into carpet pile in a way that food crumbs and dust never do. We standardized a pet-hair test rig to compare the two flagships in this category: 5 g of golden retriever hair (collected from one weekly brushing session of a single donor dog) distributed evenly across three flooring types: hardwood, low-pile carpet (Berber, ~5 mm pile), and mid-pile carpet (residential cut-pile, ~12 mm pile).
Methodology
- Test area: 8 m² zone per surface, marked with painter's tape.
- Hair distribution: weighed into 1 g portions, distributed by sieve at 40 cm height for consistent dispersion.
- Pickup measurement: pre-test weigh of empty dustbin (sub-gram precision scale, 0.01 g resolution), post-test weigh, delta is captured hair. We also visually inspected each surface and the brush roller after each pass.
- Robot settings: Max suction mode, single pass, mopping disabled, side brushes engaged.
- 5 runs per robot per surface, mean reported.
Pickup percentage (higher is better)
| Surface | Roborock S9 MaxV Ultra | Dreame X40 Ultra |
|---|---|---|
| Hardwood | 99% | 98% |
| Low-pile carpet | 96% | 94% |
| Mid-pile carpet | 91% | 87% |
On hardwood both robots are essentially tied — the difference is within measurement noise. The Roborock pulls ahead on carpet thanks to 22,000 Pa max suction (vs the X40 Ultra's 12,000 Pa) and a higher-torque main brush motor that maintains suction force even as the pile resists airflow.
Brush wrap test (after 5 sessions, lower is better)
Both robots advertise "anti-tangle" rubber-and-bristle main brushes. After 5 cumulative sessions of pet-hair pickup:
- Roborock: 0.4 g of hair wrapped around brush axle
- Dreame: 0.6 g of hair wrapped around brush axle
Neither was unmaintainable — both cleared with the included brush tool in under 60 seconds — but the Roborock's narrower brush bearings showed slightly less hair migration to the axle.
Side brush hair scatter
A common failure mode: side brushes fling pet hair away from the suction path. We marked starting hair piles and counted "scatter events" (hair displaced more than 30 cm from intended path):
- Roborock: 11 scatter events across 15 test runs.
- Dreame: 18 scatter events across 15 test runs (single 3-armed side brush is slightly more aggressive).
Noise during pet-hair mode
| dB(A) at 1 m | |
|---|---|
| Roborock S9 MaxV Ultra (Max) | 67 |
| Dreame X40 Ultra (Max) | 65 |
Both robots stay below conversation-disruption levels at normal viewing distances; the Dreame edges ahead on noise by ~2 dB. In auto mode (medium suction), both drop to 59–61 dB.
Carpet vs hardwood — which to optimize for
If your home is predominantly hardwood with rugs, both robots are excellent picks. If your home is 50%+ carpet, the Roborock's suction advantage compounds across daily cleaning and ends up with measurably cleaner carpet over a month.
Long-term pet-hair maintenance
Both robots' self-empty bases (Roborock RockDock Ultra, Dreame DocStation Ultra) handle pet-hair-laden dustbins without clogging in our 60-day stress test. Plan for a $40/year bag spend on either. The Roborock's bag has slightly better sealing — no detectable dust release on bag changes.
Verdict
On hard floors the two are essentially tied; pick on noise or app polish. On carpet, the Roborock's higher suction (22,000 Pa vs 12,000 Pa) shows in the pickup numbers — 4 percentage points on mid-pile is the difference between "looks clean" and "actually clean" after a single pass. The Dreame edges ahead on noise (~2 dB) and on threshold-climbing ability (the X40's lifting mop and 60 mm threshold are class-leading).
See the full Roborock S9 MaxV Ultra vs Dreame X40 Ultra comparison or our best robot vacuums 2026 guide for the broader category.
Turn this reading into a better product decision
This test note is a decision framework, not a substitute for checking the exact variant, regional price, availability, and warranty that apply to you. Use the linked catalog data to separate published facts from personal priorities, then compare the final shortlist directly rather than relying on a generic ranking.
Verify the fit
Open the Robotic Vacuums category page to filter the relevant field, then inspect full product profiles and the score methodology.
Keep the recommendation current
This article references 2 catalog products; use the live product pages for current specifications and comparison links.
vsMars keeps editorial judgment, normalized Mars Score inputs, and affiliate links separate. If a detail is missing or out of date, report it so the catalog and this article can be corrected.