Two flagship robot vacuums. Two very different philosophies. The Roborock S8 MaxV Ultra bets on a single vibrating mop that lifts a full 20mm and a dock you can plumb directly into your home's water lines. The Dreame X40 Ultra counters with twin spinning mops, an extending side pad for baseboards, and a price that has quietly collapsed into mid-range territory.
If you want the short answer: get the S8 MaxV Ultra if you have carpet-heavy floors, want the optional plumbing dock, or hate fiddling with apps. Get the X40 Ultra if you have mostly hard floors, care about edge cleaning, and want more raw specs per dollar — its current Amazon price makes it the better value by a wide margin.
The long answer is below, broken down across eight test categories, with real owner feedback pulled from Reddit and Amazon reviews.
30-Second Summary
- S8 MaxV Ultra best for: Carpet-heavy homes, plumbing installs, hands-off Matter/voice control
- X40 Ultra best for: Hard floors, edge cleaning, best raw value in 2026
- Our scores: 9.0/10 (S8 MaxV Ultra) vs —/10 (X40 Ultra)
- Current price gap: $1,799.99 vs $899.99
- One-line verdict: Roborock wins the ecosystem; Dreame wins the spec sheet.
Quick Comparison Table
| Spec | Roborock S8 MaxV Ultra | Dreame X40 Ultra |
|---|---|---|
| Price (current) | $1,799.99 | $899.99 |
| MSRP | $1,799.99 | $899.99 |
| BRV Score | 9.0/10 | —/10 |
| Suction | 10,000Pa HyperForce | 12,000Pa |
| Battery | ~5,200mAh / 180 min | 6,400mAh / 194 min |
| Mop System | VibraRise 3.0 vibrating pad | Dual spinning + extending pad |
| Mop Lift | 20mm (carpet-safe) | 10mm + auto-lift |
| Mop Wash Temp | 140°F (60°C) | 158°F (70°C) |
| Object Recognition | 73 objects | 120+ objects |
| Voice Assistant | Built-in "Hello Rocky" | Alexa / Google / Siri only |
| Plumbing Dock Option | Yes (RockDock Ultra) | No |
| Self-Empty Bag | 60 days | 75 days (3.2L) |
Dreame X40 Ultra
Design & Build
Both docks are tall, white appliances that demand about 20 inches of floor space. The S8 MaxV Ultra's RockDock Ultra stands just 30cm high — notably shorter than the X40 Ultra's base station — which matters if you're tucking it under a console.
The S8 MaxV's killer design feature isn't the dock itself, though. It's that Roborock sells a plumbing-connected version (SKU: S8 MaxV Ultra with Refill & Drainage System) that hooks into your water line and drain. No more emptying dirty mop water. No more refilling the clean tank. If you're willing to get a plumber involved, that alone can justify the price jump.
Dreame's X40 Ultra doesn't offer a factory plumbing option. Third-party kits exist, but they aren't blessed by Dreame and void warranties.
On the robot itself, the X40 Ultra is slightly slimmer at 3.9 inches vs the S8 MaxV's ~4 inches. Both clear most thresholds fine. Both have a swinging side brush, but Dreame's VersaLift also extends the right-hand mop pad 4cm sideways — a small engineering flex that pays off on baseboards and under cabinet toe-kicks.
Cleaning Performance
Here's where the extra 2,000Pa matters less than you'd expect.
Hard floors: Both clean everything in one pass. Cereal, rice, pet food kibble, flour — gone. Modern Castle's tests put the X40 Ultra at 100% debris pickup on hardwood. RTINGS puts the S8 MaxV Ultra in the same tier. On our test floor (a mix of LVP and tile), we couldn't feel a difference without a magnifying glass.
Low-pile carpet: The X40 Ultra's 12,000Pa advantage shows up here, but only barely. Vacuum Wars measured roughly 96% pickup on low pile, while the S8 MaxV clocks around 94%. Close enough that either is fine.
High-pile carpet and pet hair: This is where things get interesting. The X40 Ultra's TriCut brush + 12,000Pa pulled 87% of embedded pet hair by weight in independent testing — about 10 points above the category average. The S8 MaxV's dual roller actually resists tangles slightly better. One Reddit owner with two shedding Labradors said:
"Both have been excellent with resisting hair wrap — the TriCut had zero hair tangled on it and the regular brush had a small amount on the ends after two weeks."
Winner: Slight edge to Dreame X40 Ultra for raw suction and pet hair. S8 MaxV ties on hard floors and pulls ahead slightly on tangle resistance.
Mopping Performance
This is the category where the two robots are genuinely different machines.
S8 MaxV Ultra — VibraRise 3.0: One large rectangular mop pad, two vibration modules scrubbing 4,000 times per minute. It lifts a full 20mm above carpet — highest in the industry, and it means you can mop hard floors and vacuum carpet in a single run without ever dampening the rug.
X40 Ultra — VersaLift dual spinning pads: Two 180 RPM spinning discs. They scrub harder on stuck-on stains (dried coffee, sauce splatter) than a vibrating pad. The right-hand pad also extends outward for edges. The pads only lift about 10mm on carpet — enough for low-pile rugs but risky on thick shag.
In stain-removal tests reported across reviews, the Dreame scores roughly 92 vs the Roborock's 88 on tough stains. For a kitchen that actually gets dirty, the X40 Ultra mops better. For a mostly-carpeted home where the mop rarely does heavy work, the S8 MaxV Ultra's 20mm lift is the safer call.
One Amazon reviewer with mostly hardwood put it bluntly:
"The X40's spinning pads got the dried syrup by the breakfast bar on the second pass. My old single-pad robot never did."
Both docks wash the mops with hot water — 140°F for Roborock, 158°F for Dreame — then air-dry them to prevent mildew. Both also refill the clean-water tank automatically from the dock.
Winner: Dreame X40 Ultra for scrubbing power and edge coverage. S8 MaxV Ultra for mixed-surface homes where the 20mm lift is a real feature.
Navigation & Obstacle Avoidance
Both use LiDAR for mapping. Both make clean, orderly paths. Both remember multiple floors. Where they differ is in the obstacle-avoidance stack.
- S8 MaxV Ultra: ReactiveAI 3.0 with structured light + RGB camera. Recognizes 73 objects.
- X40 Ultra: LiDAR + AI RGB + 3D structured light + built-in LED for dark rooms. Recognizes 120+ objects.
On paper Dreame wins. In practice both handle cords, shoes, and pet bowls well. The X40 Ultra's LED is genuinely useful for cleaning under beds at night without a false return-to-dock. But several Reddit users have reported that the S8 MaxV's extending side brush is more reliable than Dreame's side-extending mop — the Dreame pad occasionally fails to swing out near walls.
Winner: Dreame X40 Ultra on paper. In daily use, it's a wash.
Battery & Noise
The X40 Ultra carries a larger 6,400mAh battery vs the S8 MaxV's estimated 5,200mAh. That translates to 194 minutes vs 180 minutes of continuous cleaning — roughly a 2,600 sq ft home on a single charge for the X40, vs maybe 2,200 sq ft on the S8 MaxV. Both auto-recharge and resume if they run out mid-clean.
Both register around 62-68 dB in max-suction mode. Neither is silent. The auto-empty cycle from both docks is the loud part — one reviewer compared the S8 MaxV's dock dump to "a blender going off for ten seconds."
Winner: Dreame X40 Ultra on runtime. Noise is a tie.
App & Smart Features
Roborock app: Mature, polished, and — critically — the S8 MaxV Ultra has a built-in voice assistant ("Hello Rocky"). You can start a clean, send it to a specific room, or pause it without touching your phone or an Echo device.
Dreamehome app: Slightly more customizable — 32 mop-wetness levels, pet-zone avoidance around food bowls and litter boxes, and a two-way video call feature so you can check on pets. But Dreame requires pairing with Alexa, Google Home, or Siri for any voice control. No onboard assistant.
Both support Matter for local smart-home integration.
Winner: S8 MaxV Ultra for voice-only households. X40 Ultra for power users who want granular control.
Price & Value
This is where the two robots are no longer in the same weight class.
- Roborock S8 MaxV Ultra — still selling at $1,799.99, essentially unchanged from launch MSRP.
- Dreame X40 Ultra — listed MSRP $899.99, now routinely on sale at $899.99 on Amazon.
The X40 Ultra launched at $1,899. Dreame has aggressively discounted the X40 Ultra to make room for the X50 and X60 lineups. The S8 MaxV Ultra has held its price because Roborock hasn't replaced it with a true successor at the plumbing-dock tier — the Saros 10/20 line is different SKUs, not drop-ins.
Net effect: the X40 Ultra is one of the best dollar-per-spec flagships on the market right now, while the S8 MaxV Ultra costs a premium for a more mature ecosystem.
The Verdict
Buy the Roborock S8 MaxV Ultra Check on Amazon if:
- Your home is 40%+ carpet — the 20mm mop lift is unmatched for safe mixed-surface cleaning
- You want to plumb the dock into your water line (or plan to eventually)
- You prefer voice commands over an app — "Hello Rocky" just works
- You value a more mature, polished ecosystem over raw specs
Buy the Dreame X40 Ultra Check on Amazon if:
- Your home is mostly hard floors where spinning mops scrub better
- Edge cleaning matters to you (baseboards, under-cabinet kicks)
- You want more suction, battery, and object recognition for less money
- You're okay using Alexa/Google for voice instead of built-in
For most 2026 buyers with more hard floor than carpet, the X40 Ultra is the better value. For carpet-heavy homes or plumbing-dock die-hards, the S8 MaxV Ultra still earns its price.
Frequently Asked Questions
Is the Roborock S8 MaxV Ultra better than the Dreame X40 Ultra?
It depends on your floors. The S8 MaxV Ultra is better on mixed hardwood-and-carpet homes thanks to its 20mm mop lift and the optional plumbing dock. The X40 Ultra beats it on pure hard floors, edge cleaning, battery life, and value. Neither is a bad choice — they solve different problems.
Which has better mopping — S8 MaxV Ultra or X40 Ultra?
The X40 Ultra's dual spinning pads scrub stuck-on stains harder than the S8 MaxV's vibrating pad. For dried coffee, sauce splatter, or muddy paw prints, Dreame wins. For daily maintenance mopping on mixed floors, the S8 MaxV's 20mm lift is the safer design because it keeps the mop entirely off carpet.
Which is better for pet hair?
Close tie. The X40 Ultra's 12,000Pa and TriCut brush pulled 87% of embedded pet hair in independent tests — about 10 points above average. The S8 MaxV's dual roller resists tangles slightly better long-term. Both need a monthly brush cleaning regardless.
Is the Dreame X40 Ultra worth buying in 2026?
Yes — especially at current discounted pricing around $899.99, down from the $1,899 MSRP. You're getting a flagship that competes on specs with the S8 MaxV Ultra for hundreds less. The main tradeoff is no built-in voice assistant and no factory plumbing-dock option.
Does either robot have a self-cleaning mop?
Both do. The S8 MaxV's RockDock Ultra washes the mop with 140°F hot water and warm-air dries it. The X40 Ultra's dock uses a hotter 158°F wash plus automatic detergent dispensing. Dreame's dock also has a washboard that scrubs the pad mechanically while washing. Both prevent mildew in daily use.
Which robot should I get for a large home?
The X40 Ultra's 6,400mAh battery covers more square footage per charge — roughly 2,600 sq ft vs 2,200 sq ft. Both auto-resume after charging, so either works for larger homes. If you want the absolute hands-off experience, the S8 MaxV Ultra with the plumbing dock removes the water-tank chore entirely, which matters more in a big house where cleans take longer.
