Closeup picture of the Dreame X40 Ultra dock and robot

Dreame X40 Ultra review: Advanced robotic cleaning

The Dreame X30 Ultra has barely hit the market, but its successor is already here: the Dreame X40 Ultra. Although both models look similar, the new Dreame X40 Ultra features several improvements over the Dreame X30 Ultra. These include 70ºC hot water mop washing and better sensors for dirt and obstacle detection. The robot also comes with an impressive 12,000Pa of suction power, among the strongest available. In addition, it comes with the same feature the Roborock S8 MaxV Ultra has: an extending side brush to clean corners.

Side view of the Dreame X40 Ultra and its dock

In this detailed review, let’s see how the Dreame X40 Ultra’s features improve the cleaning performance and experience.

Dreame X40 Ultra

Vacuuming efficiency
Mopping efficiency
Obstacle avoidance
Battery life
Value for money
Design & build quality


The Dreame X40 Ultra is a powerful robot vacuum cleaner with an extending side brush for thorough cleaning. It also mops well, thanks to an extending side mop and automatic detergent usage. However, it doesn't handle obstacles well, and requires a bit too much dock maintenance. While innovative, the Roborock S8 MaxV Ultra is a better choice for the same price thanks to its superior performance in most areas.

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Elegant design, but identical to the Dreame X30 Ultra

Although the Dreame X40 Ultra is a different model, it looks almost identical to the X30 Ultra. This is especially true of the dock, which is visually the same. It’s vertically arranged, with two water tanks at the top, covered by a thin lid. The front features vertical stripes that add up to the overall premium appearance. On the lower half, a golden cover conceals the dust bag and detergent tank. The baseplate has the same rotating scrapers as the X30 Ultra, designed to keep the dock clean. However, although the washing board is removable, it comes with small holes in it, thus allowing water and dirt to pass through.

Dreame X40 Ultra dock and robot

The robot maintains a classic appearance, with a circular shape and a top LiDAR dome. There’s also a flap to access the HEPA filter and dust bin. Looking more closely, the robot comes with subtle differences compared to the X30 Ultra. These include multispectral sensors at the front for precise obstacle detection. Most importantly, there’s now a motorized side brush, just like the one Roborock introduced on the S8 MaxV Ultra. It can automatically deploy to clean corners and along furniture.

Underside of the Dreame X40 Ultra with the mop pads, roller brush, and side brush

The Dreame X40 Ultra also has two rotating mop pads, one of which can extend. This allows it to reach baseboards and corners more effectively. As standard, the robot comes with a single rubber roller brush. In addition, Dreame also sells an optional TriCut brush, which minimizes hair and pet fur entanglements by cutting them.

Closeup picture of the Dreame X40 Ultra dock showing the Dreame logo

The overall build quality is good. Both the robot and dock are sturdy and use premium plastics. However, for a product at this price, some parts seem a bit fragile, particularly around the hatches.

Comprehensive app, with plenty of options

This Dreame app guides you through the setup and mapping process. While creating the map, the robot automatically identifies and segments rooms. It can save up to four different maps and automatically position itself, which is convenient if your house has multiple floors. You can then rename rooms, split or merge them, as well as create virtual barriers and specific cleaning settings for each room.

The Dreame X40 Ultra comes with an AI mode called CleanGenius. It automatically adjusts the cleaning settings and can automatically initiate a second pass in rooms where it senses dirt. You can, of course, manually adjust these settings, including the suction power, mop humidity, and the frequency of mop washing. Likewise, you can set a custom cleaning sequence, or have the robot vacuum before mopping, rather than doing both simultaneously.

You can also adjust the robot’s behavior when encountering carpets. It can automatically lift its mop pads over carpets, ignore them, or even detach the pads and leave them in the dock. Similarly, the settings for extending the mop and side brush are customizable, as well as the addition of detergent and the mop washing temperature.

The robot also boasts an RGB camera, which lets you remotely monitor your home. Moreover, the X40 Ultra can even take a picture of obstacles and place them on the map.

The Dreame X40 Ultra lacks an integrated voice assistant and Matter connectivity. It is, however, compatible with Google Assistant and Alexa.

Outstanding vacuuming performance

The Dreame X40 Ultra comes with an outstanding 12,000Pa suction power, which is one of the highest we’ve seen on a robot vacuum. It uses a bristleless brush roller, which helps it capture dirt and dust, without requiring heavy maintenance and care. In addition, the motorized side brush enables it to clean corners and along baseboards effectively.

Dreame X40 Ultra with the top flap open, showing the HEPA filter and dust bin

The suction performance is excellent on both hard floors and carpets. The robot can capture floor dirt and clean corners effectively, especially thanks to the extendable side brush. The latter deploys automatically when needed, and sends dirt to the brush roller to be vacuumed.

Dreame X40 Ultra dock, showing the dust bag and detergent tank

Even when using the lowest suction power, hard floors are effectively vacuumed. On carpets, the robot automatically boosts its power, allowing it to reach deep into carpet fibers to extract dust and dirt. Additionally, the robot can detach and leave its mop pads in the station when in vacuum-only mode or when cleaning carpets, thus avoiding wetting them.

Good mopping results, but could do better

When mopping, the Dreame X40 Ultra yields good results. It uses two rotating mop pads, which are washed before, during, and after each cycle using hot water. The MopExtend feature allows the right pad to automatically extend and clean edges and baseboards. Also, thanks to the detergent tank, the dock automatically mixes the right amount of cleaning solution with water for better results.

Dreame X40 Ultra front with the mop pad extended and the dock in the background

In practice, the overall results are good, and most stains and dirt are removed after a single pass. However, unlike with competing products, the mop pads are cold when the robot leaves the dock. This makes the cleaning effect less effective, especially on tough, greasy, or dried stains. As a result, the robot leaves some streaks on the floor when encountering particularly dirty floors, and may need to clean them a second time for best results.

Dreame X40 Ultra water tanks with the dock in the background

Indeed, when detecting dirty areas, the Dreame X40 Ultra automatically triggers a second pass or generates a map of the rooms it recommends cleaning a second time. However, the new Roborock models, the X40 Ultra performs a second pass in an entire room it considers dirty, rather than focusing on a specific area.

Dreame X40 Ultra dock showing the water tanks

The MopExtend feature works well, and the robot automatically adjusts the mop extension, unless you choose to extend the pads during each cycle. Dreame improved the feature compared to previous models, as there is no longer an uncleaned strip. Similarly, in mopping only mode, the robot automatically lifts both the roller brush and side brush, preventing unnecessary friction with the floor.

Navigation and obstacle detection

Overall, the Dreame X40 Ultra is a good navigator. It moves from room to room without getting stuck or lost.

Dreame X40 Ultra front with the dock in the background

However, its obstacle detection isn’t the best. Indeed, the robot detects for obstacles when entering each room, but doesn’t continuously scan for them. This means that if the robot detects an obstacle, which is then removed, it will think it is still there and avoid it. Also, it tends to leave a relatively thick margin around obstacles, resulting in a large uncleaned area around them.

Quiet and long-lasting

The Dreame X40 Ultra is relatively quiet, despite its high suction power. The lowest suction power is barely audible, and does not interfere when watching TV or working. Of course, the maximum setting is much louder, but is mainly useful on thick rugs.

Dreame X40 Ultra top view with the mop pad extended

The battery offers a runtime of about 180 minutes, which is more than enough to clean a surface area of about 150 m2. If the battery is low, the robot returns to its docking station, recharges, and resumes where it left off.

Easy to care for, but not maintenance-free

The Dreame X40 Ultra promises a nearly autonomous cleaning experience. Its docking station comes with large water tanks, meaning you don’t need to empty or fill them too frequently. The detergent tank also means you do not need to manually add cleaning solution every time you refill the tank.

Dreame X40 Ultra detergent tank with the robot in the background

Maintaining the robot is a breeze, especially thanks to the bristleless roller brush, which minimizes hair tangles. The optional TriCut brush cuts hair and animal fur before they can tangle, promising even less maintenance.

Dreame X40 Ultra dock, showing the dust bag and detergent tank

The docking station also pampers your mop pads, using hot water at 70ºC and hot air to clean and dry them, limiting bad odors. However, the washing board is not as effective as a dedicated high-speed brush, like the one on the Roborock S8 MaxV Ultra. Thus, the mop pads tend to get dirty after a while and require machine washing about once a month.

Dreame X40 Ultra baseplate and washing board

Additionally, its hollow design means that water flows into the lower part of the base, which must then be cleaned. Fortunately, a dedicated cleaning mode for the baseplate fills it with water, prompts you to scrub with the provided brush, and then automatically collects the dirty water. However, a smarter design like that of the Ecovacs Deebot T30 Omni would have been simpler to maintain.

Is the Dreame X40 Ultra the right robovac for you?

The Dreame X40 Ultra is an effective but expensive robot. Its vacuuming efficiency is impressive, thanks to the highest suction power we’ve seen on the market. In addition, its extending side brush ensures corners and baseboards are properly cleaned. Mopping results are also good, as the robot handles most stains reliably.

However, unlike other robots, the mop pads come out cold, despite using “hot water”. Moreover, the robot struggles to manage obstacles, either assuming they have not been moved or staying too far away from them. Finally, maintaining the dock is more complex than on some models, despite a self-cleaning feature promised by the brand.

Overall, it’s a very good product full of innovations. However, at this price point, the Roborock S8 MaxV Ultra generally outperforms the Dreame X40 Ultra in cleaning results and obstacle detection. The choice is not so easy, as the design also weighs in on the decision, as does using other products from the brand in a single application.

Vacuuming performance“Hot” water doesn’t seem hot
Baseboard and corner cleaningAwkward obstacle detection
Comprehensive appDock isn’t “self-cleaning”


What are the key differences between the Dreame X40 Ultra and the Dreame X30 Ultra?

The Dreame X40 Ultra features an extending side brush for cleaning corners, better sensors for detecting dirt and obstacles, 70ºC hot water mop washing, and a more powerful suction of 12,000Pa compared to the Dreame X30 Ultra.

How does the extending side brush on the Dreame X40 Ultra work?

The motorized side brush on the Dreame X40 Ultra can automatically extend to better clean corners and along furniture, ensuring that dirt is efficiently collected.

Can the Dreame X40 Ultra automatically adjust its cleaning settings?

Yes, the Dreame X40 Ultra features an AI mode called CleanGenius, which can adjust cleaning settings based on the area it’s cleaning and even initiate a second pass in dirtier rooms automatically.

Does the Dreame X40 Ultra dock require maintenance?

While the Dreame X40 Ultra offers a nearly autonomous cleaning experience, its mop pads require regular machine washing, and the docking station’s lower base needs occasional manual cleaning.

Does the Dreame X40 Ultra use hot water for mop washing?

Yes, the Dreame X40 Ultra utilizes hot water up to 70ºC for mop washing, which helps in achieving more effective cleaning and disinfection of floors. However, the mops systematically come out cold.

Kyle Lakewood

Based in New York, Kyle combines his passion for smart home products with a commitment to honest, unbiased reviews. As the founder of Smart Home Critic, he guides readers in choosing the right products for their needs. Living with his partner and dog, Kyle brings a personal touch to his work, involving his whole family in the review process to ensure each product is thoroughly tested and family-approved.