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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  • GenSozo - Tuesday, April 16, 2013 - link

    I want to mount a Mini-ITX system in this beast then tape a pair of hipster glasses on the top. LAN parties here I come.
  • hero1 - Tuesday, April 16, 2013 - link

    That'll be insane. I have been waiting for this case for so long. Now that it's here, I will consider purchasing it even though I have the XL R2 fitted with Noctua fans and H100i and runs cold. This will be a perfect purchase with a couple of Titans, hydrocopper versions that is. Drool!
  • Blibbax - Tuesday, April 16, 2013 - link

    Wasted on <4 watercooled cards. Stick with your XL.
  • DanNeely - Tuesday, April 16, 2013 - link

    The XLR2 doesn't have room for anything larger than a 280mm rad; that's tight for cooling SLI/xFire cards if you also have the CPU in the loop.

    Also even if you're not filling them to the max, extra large cases are easier to work on because you've got a lot of extra space to fit your hands into and more freedom in how you place components as a result. If you're on a budget and trying to maximize bang for the buck an oversized case is an easy first thing to cut but they do make building/upgrading much easier.

    As long as you've got the height and upper body strength to handle the size/weight anyway. :)
  • hero1 - Tuesday, April 16, 2013 - link

    The XL R2 is very tight case. I figure that I could have a 280mm rad for the front but this means I have to get rid of my H100i and add another 280mm rad up top in order to cool SLI/XF with CPU in the loop. It's doable and I will consider it but the space does indeed become very tight. I think I can have the back and bottom fans as intake and exhaust through the top and front.

    Can handle that weight easily but someone below mentioned the case labs products. I have been looking at what they have to offer and go from there. The only thing that Corsair has them beat is the aesthetics with regards to how the case is assembled.
  • TaylorSandler - Thursday, April 18, 2013 - link

    Love my job, since I've been bringing in $5600… I sit at home, music playing while I work in front of my new iMac that I got now that I'm making it online.(Click Home information)
  • spikey27 - Tuesday, August 26, 2014 - link

    Dan, you've hit on one of my pet peeves - it's no fun working in a case without enough space to use your hands. It so much nicer to be working in a spacious case.

    I'm in the process of going from a Codegen S-101 to the 900D, and looking forward to it.
  • IDUEHE - Thursday, May 2, 2013 - link

    Wonderful..... University of Nigeria
  • hero1 - Tuesday, April 16, 2013 - link

    This is an awesome case that will serve us better, those who are willing to go all out on watercooling, custom that is. I hope that they make something like it that fits right between the 650D and 800D with the same cooling capabilities minus a couple of 5.25 drive bays.
  • DanNeely - Tuesday, April 16, 2013 - link

    At this price all the external USB ports should be USB3 to futureproof it. Since most current mobos only have 1 or 2 USB3 headers, include a pair of USB3 to USB2 header adapters so the ports can be fully utilized now.

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