Same family, same core cleaning hardware, but two different takes on the dock. The X40 Master pairs a larger dust bag and a shorter, wider base station with built-in voice control and an extra LED to help it see obstacles in the dark, making it the pick for pet homes and big open floor plans. The X40 Ultra keeps the same dual spinning mops and LiDAR navigation in a slimmer, taller dock that costs considerably less, which makes it the sensible buy for most households.
Both of these Dreames run the same dual spinning mop pads, the same single rubber main brush, and the same LiDAR plus camera navigation stack. So the decision here isn't about which one cleans your floors better. It's about docks, coverage, and how much you want to pay for a handful of extras. The Master adds a bigger dust bag, built-in voice control that works without a phone or speaker, and an LED to help its camera see in dim rooms. The Ultra strips a few of those away and lands at a much friendlier price. That gap is where this comparison actually lives.
Dreame X40 Master
out of 10Dreame X40 Ultra
These two land close overall, 8.0 for the Master versus 8.3 for the Ultra, so neither is a bad call. The Master edges ahead on navigation, 8.6 versus 8.0, helped by that extra LED illuminator for low-light obstacle spotting, and it takes cleaning 7.1 versus 6.8. Features tie dead even at 9.5 each, which makes sense given the shared hardware. Value is where they split hard: 5.5 for the Master against 9.4 for the Ultra, driven almost entirely by price.
Start with the docks, because they look nothing alike. The Master's station is short and wide at 11.0 inches tall and 19.1 inches deep-ish in footprint, so it tucks under a console table but eats more floor. The Ultra's stands 23.2 inches tall with a shallower 13.4-inch depth, better for a narrow hallway nook. Inside, the Master holds a 4.2L dust bag against the Ultra's 3.2L, roughly a month of extra breathing room in a shedding household. The Ultra's dock carries a 4.5L clean water tank and 4L dirty water tank for mop washing across many sessions. Voice control differs too: the Master adds a built-in assistant on top of Amazon, Google, and Apple support. And the Master covers 3,315 square feet on a single 198-minute charge.
Both use the same single rubber main brush, which resists hair tangles better than bristle designs and handles the transition from hardwood to low-pile carpet without drama. There's no hardware difference here worth choosing between.
Dual spinning mop pads on both, which is the strong tier of mopping tech. Spinning pads press down and actively scrub rather than passively dragging, so dried coffee splatter and kitchen grime actually come up.
The Master's 4.2L dust bag beats the Ultra's 3.2L, and with a golden retriever in the house that difference means fewer trips to swap bags. Both share the same tangle-resistant rubber brush.
LiDAR plus AI camera plus 3D structured light on both, so they map accurately and dodge socks and charging cables. The Master adds an LED illuminator, which helps its camera identify obstacles in dark rooms or under furniture.
Both docks empty the dustbin and wash the mops automatically. The Master's larger dust bag stretches out the interval between bag changes, and its 11.0-inch height slides under most furniture rather than standing 23.2 inches tall like the Ultra's.
The Master covers 3,315 square feet on a single 198-minute run, which is enough for most multi-room homes in one pass without a mid-clean recharge break.
Both handle Amazon Alexa, Google Assistant, and Apple, plus no-go zones and multi-level maps for multi-story homes. The Master layers on built-in voice control, so you can bark a command at the robot itself without reaching for a phone or smart speaker.
| Feature | Dreame X40 Master | Dreame X40 Ultra |
|---|---|---|
| Charging Dock Height | 11.0 in | 23.2 in |
| Smart Obstacle Avoidance Technology | AI + camera + 3D structured light + LED | AI + camera + 3D structured light |
| Voice Control Platforms | Built-In, Amazon, Google, Apple | Amazon, Google, Apple |
| Dust Bag Capacity | 4.2 L | 3.2 L |
| Charging Dock Depth | 16.8 in | 13.4 in |
| Robot Height | 4.1 in | 3.8 in |
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The cleaning hardware is identical, so you're really picking a dock and a price. The Ultra gives you the same mopping and navigation for far less, which suits most buyers. Go with the Master only if the bigger dust bag, low-profile dock, or built-in voice control solve a specific problem in your home.
