In and Around the Corsair Obsidian 650D

Externally the Obsidian 650D is basically the mid-tower version of Corsair's larger 700D and 800D enclosures, and people who aren't fans of the Graphite 600T's curved design are liable to appreciate the monolithic black style. About the only thing that might seem out of place is the window on the left panel; I have a sort of "take it or leave it" feeling about windows on cases and would probably prefer either a solid panel or a 200mm fan intake.

The front of the enclosure is very spare and clean. It's almost entirely black aluminum, with four drive bays. The power button and HDD indicator light are both above the bays along with a door that hides the front I/O. It's a nice stylistic touch but I'll admit I found myself wishing that door was an external 3.5" bay for a card reader; your mileage may vary and I certainly can't ding Corsair for the decision since inside and out, it looks good. Behind that door is also the reset button and frankly that's probably a perfectly fine place for it. Below the bays is a removable fan filter for the front 200mm intake fan.

When you get to the top of the 650D, you'll find the SATA hot-swap bay and fan controller hidden by a sliding plastic door. The door on my review unit was a little bit stiff, but it did work fine otherwise. The bay will easily accommodate a 3.5" or 2.5" drive. Behind it is the massive vent for the top-mounted 200mm exhaust fan, and this is a big improvement on the 600T's design. The vent here is perfectly flat and can accommodate a pair of 120mm or 140mm fans instead of the 200mm fan for larger water-cooling radiators. What I really appreciate here, too, is that the removable filter on the top of the 600T is gone and the vent is just built into the case. That filter was a nice enough touch, but over the last few months mine has actually developed a bit of a rattle that requires "concussive maintenance" to silence from time to time. On boutique builds it also had a habit of getting stuck.

Finally, the back and bottom are pretty standard fare. The bottom of the case has a removable filter to go under the power supply's intake fan and is lifted off of the ground to allow you to place the case on carpet, while the back has a small hole for routing the USB 3.0 passthrough cables along with a generous eight expansion slots (one more than the pricier 700D and 800D cases), a 120mm exhaust fan, and two rubber-lined holes for passing water-cooling tubing.

Internally, the 650D is an exercise in deja vu. I have been inside this case before. Corsair retains the latched side panels found on the 600T and these are still one of the best features I've ever seen on any case, period. Getting into and working inside the 650D remains just as easy as the 600T was, so if you're the tinkering type Corsair has your back. Unfortunately, though, the side panels on the 650D don't feel quite as secure and don't go back on quite as easily as the 600T's did, and I could see with the 650D where they might develop a rattle over time.

But the inside design is stellar. The two three-drive cages both feature tool-less drive trays that can support 2.5" or 3.5" drives, once again making a strong argument for using drive trays in modern designs. The top cage can also be removed and placed alongside the bottom one to allow for extremely long video cards, though I doubt that will be necessary: there's already 13.5" of clearance to begin with. Corsair also includes a generous opening in the motherboard tray for mounting heatsinks, and there are an abundance of openings with which to route cables behind the tray.

If I have one complaint to really carry over from the 600T, it's the power supply mounting system. Corsair includes an additional, movable support for the power supply, but it's held in place by two thumbscrews and frankly it's extremely awkward, can be difficult to line up, and is ultimately superfluous. This is an extra piece of complication the case just doesn't need, and hopefully in a future revision they'll just eschew it entirely. It allows for tool-less power supply mounting, but it's just not necessary.

Introducing the Corsair Obsidian 650D Assembling the Corsair Obsidian 650D


View All Comments

  • HilbertSpace - Friday, July 29, 2011 - link

    This case is great once you get rid of the 200 mm fans (far too loud). I replaced the top 200 with two 120 mm fans running at 500 rpm, replaced the back 120, and front 200 mm with a 140 mm fan (this requires your own mounting solution as there are only mounting points for 200 mm fans).

    Not it's nice and quiet - on par with my old Antec Solo case (similar to Sonata). I only hear a slight bit of air movement noise.

    The side window panel can be replaced for $20-25 with a solid one from Corsair's website.
  • Aikouka - Friday, July 29, 2011 - link

    I own a CNPS9000, and I'm curious how you like the 9900? My biggest gripe on the 9000 is that I believe they were phasing out the product at NewEgg, and all I could get was one with a silly green LED. At least my PC is fast and furious (and cool). ;) Reply
  • varneraa - Friday, July 29, 2011 - link

    I'm not familiar with the cooler you are using, but I wonder if you could significantly improve the thermals by orienting the cpu cooler to exhaust through the top of the case and then have the rear 120mm fan pull air into the case. Reply
  • Dustin Sklavos - Friday, July 29, 2011 - link

    I actually tried that with my 600T and it made virtually no difference, so it's reasonable to assume that wouldn't help the 650D either. Reply
  • Meghan54 - Friday, July 29, 2011 - link

    " doesn't change the fact that you're exhausting more air than you're bringing in."

    Did you even read what you wrote, Mr. Sklavos? Do you think, using the fans that come with this or any other computer case, that you can create a negative pressure inside the case in relation to the outside atmospheric pressure? And in the above quoted line, you seem to imply that the case can be imploded due to the fact that a partial vacuum is being created inside the case, since you're saying the fans are exhausting more air than comes into the case.

    Of course, that is utter bullshit. Why?

    First, the case would have to be completely air tight to have the "more air out than In" phenomenon to occur. Second, the fans must be capable of tremendous static pressure to actually suck more air out of a case than moves into the case. Given what the author has said, eventually the case would implode as an end result of all that "negative pressure" being created and given enough running time.

    But we all know case fans do not have very high static pressure output curves and neither are computer cases air tight. Therefore, the air exhausting from the case exactly equals the amount of air entering the case, nothing else can be happening.

    Where does the air get into the case, then? Between the optical drives or drive covers, around the side panels, through the rear venting.....all avenues of air infiltration or exhaust, depending on how the fans are arranged. You can have every single fan blowing into the case you want, you won't have tremendously increased positive pressure, if any at all, because the air will escape via every seam, crack and crevice it can find. And even using ultra high output fans, I doubt anyone's seen a case either implode from too much negative internal pressure nor explode from too much positive internal pressure.

    Honestly, about all one can do is direct the movement of air within a case with fan air flow, not increase internal air pressure in any meaningful amount, especially given what are typically used for case fans (low noise, low rpm large fans.)

    Simply, put a lot of fans blowing into a case and you'll have exhaust of the exact same amount of air put into the case from every seam, crack, hole, and crevice found in the case. Put a lot of fans exhausting air from a case and you'll have an equal amount of air entering the case through the same cracks, holes, crevices, and grills in the case. Our fans are not strong enough to either create a partial vacuum or partial positive pressured environment within any steel/aluminum/plastic enclosure that leaks air around and through multiple seams found on every case.....they're not air tight.
  • Dustin Sklavos - Saturday, July 30, 2011 - link that is some physics rage. Reply
  • Casper42 - Monday, August 01, 2011 - link

    Way to go all agro on an assumption.

    The case will implode?
    Did we read the same article?

    Here is the deal Mr Wizard, if you Push more air into the case than you exhaust, you get leakage coming out of the case in places you might not want. If you pull more air out of the case than you push in, then you get the same leakage in reverse. You have air sneaking in places you were not intending. This is exactly what you are saying in that the case is not airtight.

    The problem with both of those is 2 things as I see it.
    1) You stand a higher chance of recirculating hot air back into the case
    2) Your fans have to work harder due to the unbalanced airflow.

    I don't think number 2 is a big deal, as you rightfully mentioned that today's craptastic PC fans don't stand up well when it comes to large amounts of static pressure so the impact of such pressure on fan rotation and resistance is negligible at best.

    But the problem with air coming in or leaking out from places you dont want is one that should be rectified. And as I read it, thats really what the writer was trying to say.

    IMHO, the best way to design a case to deal with airflow is to push in more air than you have FANS to exhaust it, put the exhaust fans in strategic locations near things that need to be extra cooled (CPU, GPU and PS) and then leave some perf'd areas of the case on the exhaust side of the design to allow the excess pressure to leak out gracefully without building static pressure.
  • ckryan - Friday, July 29, 2011 - link

    In the conclusion you state a desire to see more intake air going straight to the tower. I would submit there is one prime example of this, the Lian Li PCA05 NB. The intake fan is on the back, blowing air in directly to the tower cooler which is like two inches away. With a Noctua U12 SE2 I don't even use a push fan, just one pull fan. The exhaust exits out the front, and all of the fans line up. If your primary concern is CPU temps, this is your case. GPU temps are not great however, though a reference style cooler helps. The good new is the GPU can't heat up the CPU even if the card puts all the heat into the case.

    On the other hand, there is something to be said for large, intelligent cases with good cable management - an area where the PC A05NB falls directly on it's Taiwanese face.
  • Casper42 - Monday, August 01, 2011 - link

    I have jimmy rigged a similar design but done it in reverse. Install a 120mm intake across 3 5.25" bays that shoots air right into a Zalman 9700 and then the rear 120 is exhaust. I refer to this as the upper zone because my GPU cuts off all the air the lower front 140mm is pulling in. With the GPU exhaust and some missing slot covers the 140 blows across the drives and GPU and creates a lower zone that is also pure front to back as well.

    With one case I had to put packing tape over the holes in the side panel that were for traditional "top down" coolers like the retail CPUs come with.
  • marc1000 - Monday, August 01, 2011 - link

    there is one thing i've been pointing on the comments of some case reviews here at anandtech: we can improve the thermals by turning ALL fans into intake fans, and let the hot air go out of the case by his own way on every opening. I did this in my case (a custom small micro-atx) and it worked great, but I do not have others cases to test, so this is my suggestion to people who can actually test cases.

    turn the back fan of this corsair to an intake fan, and maybe even the top fan too. let the cold air force out all hot air. I believe this would make a noticeable difference.


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