Seen from the motherboard side the Dark Base 900 looks like it was an inverse ATX case from the start. The top of the case offers a wide range of radiator-mounting options. Radiators up to 360 mm or 420 mm long can go here, as well as four 120-mm or three 140-mm fans not pushing air through radiators. Moving on to the build itself, working in the Dark Base Pro 900 was a lot of fun but it did require a lot of time and planning. Because the case is so customizable, you first must plan out what configuration you would like to go with before even installing any components. If you don’t do this, you would find yourself installing/uninstalling your components as you readjust the case. Aside from taking longer than expected to complete, the only issue I ran into during the build was working with cables at the top of the motherboard. Since the motherboard is closer to the PSU shroud when inverted, it was a little bit of work trying to plug in some things like the EPS and CPU cooler fan cables. be quiet! touts the flexibility of the Dark Base Pro 900’s interior, and I have to agree that this is one of the most adaptable cases I’ve ever seen. The motherboard tray, rear fan mount, and rear expansion slot panel are all a unit on this case, and they’re joined to its frame by six rubber-dampened screws. The tray can sit in any of three positions on the frame to balance space above the motherboard with room for expansion cards.

Unlike most PSU shrouds, the Dark Base 900 rev. 2’s isn’t joined up with the motherboard tray in the least. Instead, a generous gap between the tray and the shroud creates a full-length cable routing channel from the bottom of the case into the main chamber. This is one of the better approaches for bridging a dual-chamber case layout that I’ve seen, not least because of its versatility. Jumping ahead to an open case, we can see the bottom filter pulled out to its whole length. You can see the meshed-over side inlets for bottom intake fans. If you will recall, the bottom surface is blank. That means you can put this case on a carpet with impunity: it will not plug up your airflow. The length and accessibility of the bottom filter is also important. This case weighs 29 to 32 lbs without computer gear inside (the variation: it weighs 29 lbs. with one HDD cage, 32 lbs. with seven). It makes sense that once you put it down you will not want to move the case with its enclosed system. Having the bottom filter cover the whole bottom of the PSU to the front means that once you put it down you won’t have to move it. The filter is accessible from the front without moving the case which allows you to put the case in a cabinet.

Packaging & Unboxing

For just one example, when I put together our Ryzen Threadripper video-editing build earlier this year, mounting our 360-mm radiator in the top of that case required me to collapse the Fractal Design Define R6’s many 3.5″ bays into just two behind-the-motherboard mounting points. I had to sacrifice its 5.25″ bays in the bargain, as well. During assembly, I also had to re-mount that radiator after our initial configuration to combat a clearance issue I hadn’t accounted for. The biggest, baddest cases around tend to avoid those annoyances, and that’s apparently why they keep selling. The top panel pops off after we release several plastic tabs from the inside of the case. A look underneath reveals another layer of sound-deadening foam, plus the baffles behind the mesh we saw from the outside of the case. be quiet! claims these baffles help break up direct air flow and smooth out the case’s noise character, but they primarily appear to constrict air flow to my jaded eye. We’ll see whether that impression carries over in our performance tests. The Dark Base Pro 900 Rev. 2 looks just as premium as the price suggests. The company utilized a strange set of materials, including ABS plastic, steel, and aluminum throughout, but the end result is quite something. The front panel is actually a door that's held on by two latches and magnets, hiding the front panel dust filter and Silent Wings 3 fans. Once the build was complete, I really loved how clean it looked thanks to rubber grommets and cutouts around the motherboard tray. The included RGB LED bars (which I installed on the left side and top of the case) do an excellent job of illuminating my components and overall, I really love how unique the build looks with its inverted configuration. One thing to note is that even though the finish of the Dark Base Pro looks beautiful, it is a fingerprint magnet. It’s not a huge issue but you just have to make sure you have a microfiber cloth on standby so you can have your build look its best.

be quiet! also cleaned up the appearance of the Dark Base 900’s hard-drive mounting points in the case’s second revision. Instead of bare holes in the hard-drive mounting tray, the case now comes with plastic covers pre-installed that look more intentional than the let-it-all-hang-out approach of the past. These covers aren’t just there for better aesthetics, though—they can be popped out of the hard-drive tray to varying degrees to allow cables to pass through if needed without ruining the otherwise-clean appearance afforded by this improvement. Overall, be quiet’s Dark Base Pro 900 rev. 2 is truly an amazing case and it’s quality/design/flexibly just blew me away. Out of all the cases I have built in, the Dark Base Pro has easily been my favorite and I can’t think of any better case to give the Editor’s Choice award to.As with any case, this Dark Base 900 is not perfect. The manual is quite intricate, with instructions on doing lots of things. But the online version could be a little more detailed than our paper version. Also, I would like to have seen included spares of their unique fasteners. And there is the possibility a user might want to use top-down air-cooling. As the case is constructed the user would not have a dust filter in with that specific configuration. But overall the design was well thought out and can accommodate about any system you want to build. The be quiet! engineers continue to use fake filters in the side panel. Such a “filter” is uncalled-for in a high-end case like this one. But the designers should be given kudos for not including front and top “grills” where they were absolutely not needed. We started things off by installing an Asus AM1I-A mini-ATX motherboard and plugging in the various I/O cables. This was easy, as we had several cable-routing options available to us. We also appreciate that the case includes some pre-installed standoffs. Not every inch of the Dark Base is as well-designed, though. With flexibility comes complexity, and some parts of the case’s design suffer in the name of accommodating the Dark Base’s dizzying array of interior configurations. The power-supply mount on this case doesn’t offer juice boxes nearly enough breathing room, and some might appreciate the option to swap the noise-killing but restrictive front door with a high-airflow mesh panel.

Venture inside and it’s like an enthusiast’s playground, with lots of space to explore. Let’s start with fan mounts. There’s the usual 120/140 at the bottom, a 120/140 at the base, three 120s on the side, and three 120s or 140s both up top and in front. No love for 180s, sadly, but if you’re liquid cooling, there’s room for up to a 420mm radiator in front or up to a 360mm in the roof. Fully versatile thanks to modular construction, offering a relocatable motherboard tray, repositionable HDD slots, support for even E-ATX and XL-ATX as well as the possibility of an inverse layout

Even if the space behind the motherboard tray can get a bit messy, the main chamber of the Dark Base 900 rev. 2 ends up looking plenty clean. I especially appreciate the flexibility of the full-length cable-routing channel from the bottom chamber into the top chamber, and the trio of rubber grommets at the front edge of the motherboard proved as handy as ever for getting power and storage cabling into position. This post is more a public service for other AF 420 AIO owners, wondering if your rad will fit a Dark Base Pro 900 rev.2 Item to note: like the front filter the bottom filter uses the best dust-filtering fabric I have ever used. It is true that other OEM’s use this but it shows you that it is the best. You also get a clear view of the 140 mm front fans and the sound-deadening covering on the front door. Bottom Filter Extended

Given the largely screw-free approach, we’re surprised be quiet! hasn’t opted for a more user-friendly side panel mechanism. As it stands, the heavy tempered-glass panel is notched at eight points and has to be perfectly aligned before being slid into position and secured by captive thumbscrews. Far from a deal breaker, but in our experience, such notches can bend over time. On panels as big and heavy as this, we’d prefer a swing-to-open hinge.

System Build & Installation

The first step to inverting the Dark Base Pro 900 is pretty much removing all the internals one-by-one. We start the process with completely detaching the motherboard tray from the system by taking out the 9 screws holding it in position.