An enclosure built from the ground up for custom liquid cooling loops is actually a fairly rarefied thing. Why wouldn't it be? Building a custom loop is expensive and time consuming, which would make that type of enclosure the very definition of niche. Yet Corsair has come forward with the Obsidian 900D for one big reason: to fill that niche.

And "big" is definitely the operative word. Riding high on their liquid cooling legacy with the popular Obsidian 800D, Corsair has developed a positively massive enclosure that's designed essentially to hold the most powerful desktop machine you can conceive of while providing ample space to mount radiators and all the accoutrements of liquid cooling.

Before we get too much further into this review, I want to be absolutely clear about how the Obsidian 900D is being evaluated, because it's a very different beast from most cases. It superficially looks and is built like an overgrown ATX case, but at an MSRP of $349 it's about as premium as it gets. When you see the way Corsair designed it, you'll be able to tell like I did that it's destined for much more than a garden variety build.

What that also means is that while I have to put it through our conventional testing, that conventional testing is going to be primarily academic. Unfortunately it's much harder to tell how good an enclosure will be at its job when that job will vary from person to person in much more significant ways than just choosing which air cooler and graphics cards to use. What you're going to want to pay attention to are the feature set, ease of assembly, and overall design, and how they're going to suit your purposes. That's assuming you're in the market for a specialized case like this, and a lot of you won't be.

Corsair Obsidian 900D Specifications
Motherboard Form Factor Mini-ITX, Micro-ATX, ATX, E-ATX, XL-ATX, HPTX
Drive Bays External 4x 5.25"
Internal 9x 3.5"/2.5" (support for two additional cages for up to 15x 3.5"/2.5")
Cooling Front 3x 120mm intake fans (1x additional internal 120mm fan mount behind drive cage)
Rear 1x 140mm exhaust fan
Top 4x 120mm fan mounts (supports 3x 140mm)
Side 8x 120mm internal fan mounts (four per side, PSU blocks two of your choice)
Bottom -
Expansion Slots 10
I/O Port 4x USB 2.0, 2x USB 3.0, 1x Headphone, 1x Mic
Power Supply Size ATX
Clearances HSF 170mm
PSU 280mm
GPU 500mm
Dimensions 25.6" x 9.9" x 27.2"
649.6mm x 252mm x 691.6mm
Weight 41 lbs. / 18.6 kg
Special Features USB 3.0 via internal header
Multiple removable drive cages
Secondary power supply bay
Removable filters on all fan intakes
Price $349

Corsair's press materials highlight the fact that the case is designed for liquid cooling, but you've probably figured that out given how much I've repeated it. What you're going to want to know now are the radiator clearances, and they're a doozy.

The top fan mounts have a 110mm clearance from the roof of the case to the top of the motherboard and you can intrude on the top 5.25" bay. Unfortunately in the front of the case, there's a slight spacing between the topmost 120mm fan and the two bottom ones, so that essentially means you can only install a single 240mm radiator; there does appear to be space to install a single 140mm radiator and fan instead if you're so inclined. The back of the case supports a single 140mm radiator in the exhaust fan slot. Corsair keeps the other bulk of radiator potential in the bottom of the enclosure, where you can theoretically install a 480mm radiator on one side and a 240mm radiator on the other, with 110mm of radiator clearance to the PSU. Note that installing a radiator in the bottom chamber does mean sacrificing those drive cages.

In and Around the Corsair Obsidian 900D
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  • Subyman - Tuesday, April 16, 2013 - link

    I have a 800D and would not purchase something like this again. I really like the case, very well built, and so forth but with boutique manufacturers like Case Labs making thick, aluminum cases that weigh half as much with ridiculous customization, it seems a serious watercooling enthusiast has better choices out there. The 900D looks great and well built, but steel at $349 + 41lbs dry is rough. Believe me, a fully loaded 800D was is ***** to move! No wheel option is a little disappointing as well with something this large.
  • hero1 - Tuesday, April 16, 2013 - link

    This. I had absolutely forgotten about Case Labs as of late. And you do have a good point here and I think most people ought to know that they can have better cases for similar price or slightly more.
  • Blindsay04 - Wednesday, April 17, 2013 - link

    Case labs makes some quality stuff but their pricing is a lot more. SMH10 is $500 and that is probably the closest to the 900D
  • pensive69 - Wednesday, May 15, 2013 - link

    see? Subyman picked up on the need for wheels...
    and the case didn't seem to have what i might term
    non slip handholds either.
    that's where my insurance kicks in.
    good god
  • DanNeely - Tuesday, April 16, 2013 - link

    it would require changing the appearance slightly; but to make installing cards easier I'd suggest putting holes in the frame at the proper screw location and extending the side panel to cover them. It worked well in one of the more plebeian cases I've used.

    I've had trouble with hinged toolless latching mechanisms not being compatible with dual slot GPUs before and am leery about suggesting them for something like this; although with a watercooled card the obstruction might not be an issue.
  • minijedimaster - Tuesday, April 16, 2013 - link

    So they basically just took a Fractal Design XL R2 and modified it, slapped their name on it and called it a day.
  • santiagoanders - Tuesday, April 16, 2013 - link

    The interior is much more similar to the CoolerMaster Cosmos II
  • JFord047 - Wednesday, April 17, 2013 - link

    Which is basically Just an Antec Performance case re-jigged
  • Sabresiberian - Tuesday, April 16, 2013 - link

    Not sure why someone would question the "need" for this over the 800D. It's pretty simple:

    800D - 7 Expansion slots
    900D - 10 Expansion slots

    The 900D will simply hold a much larger mainboard. The 800D might well be crowding a third graphics card, and a fourth one would be out of the question.
  • Aikouka - Tuesday, April 16, 2013 - link

    I already own an 800D, and it's nice to see that they addressed the cable routing shortcomings in that case. It annoys me that I spent $300 on that case to see the side panel bow out because I'm routing a fairly common number of cables behind the case. While the side panel bowing doesn't really hamper you, I have found another issue with it that makes me reconsider ever buying another Corsair case. The other issue is that the 800D is limited in regard to the radiator sizes that it supports. Why is it that Corsair designed the 800D, their previous flagship case, to only support up to a 240mm radiator? If I had to guess, it's probably because Corsair was only selling a 240mm solution at this point (their H100 all-in-one). However, a few months ago, Corsair released a 280mm all-in-one solution called the H110i, which isn't even supported by the 800D!

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