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Cooler Master COSMOS S Chassis
Date: Mar 31, 2008
Author: Marco Chiappetta
Intro, Specs, and Packaging

It's not very often that we see innovation in a PC chassis.  Of course, just about every other component in a typical PC is enhanced or somehow improved on a regular basis, but chassis haven't really changed all that much in the last few years.  Aesthetically they have gotten more pleasing and diverse, new materials are being used, and there have been some acoustic improvements mostly due to the use of larger, low-RPM fans.  However, take away the fans and fascias and underneath most chassis are pretty similar.  In fact, it's not uncommon for the same chassis to be sold as numerous different models, just with different bezels on the front.

The folks at Cooler Master thouggh have made some significant strides as of late, in an effort to differentiate their products.  The Cooler Master COSMOS, was widely regarded as one of the best full towers available.  We even saw the COSMOS used for a handful of builds by Intel and NVIDIA at press events, which is a testament to its quality.  As good as the COSMOS is though, Cooler Master saw fit to further improve its design and have since released the COSMOS S.

The COSMOS S borrows from the original COSMOS design, but adds some innovative new features like touch sensitive controls, lighted inputs, and a more durable finish.

The Cooler Master COSMOS S Chassis

Cooler Master COSMOS S Chassis
Specifications and Features

Available Color Black
Dimension (W / H / D) (W) 266 x (H) 598 x (D) 628mm
Weight Net Weight: 13.8 kg; Gross Weight: 17.8 kg
Material Chassis: Al. Appearance: Al (side panel: 1.5mm)
Motherboards Extended ATX, ATX
5.25" Drive Bay 7(Exposed)
3.5" Drive Bay 4(Hidden, converted from 3x5.25 inch drive bays)
I/O Panel USB 2.0 x 4, IEEE 1394 x 1, eSATA x 1, MIC x 1, Audio x 1(support Intel HD / AC 97 audio)
Expansion Slots 7 slots
Cooling System Front fan(intake): one 120x120x25mm, 1200 rpm, 17 dBA (included),
Top fan(exhaust): one 120x120x25mm, 1200 rpm, 17 dBA (included),
Top fan: 120mm x 2(optional),
Rear fan(exhaust): one 120x120x25mm, 1200 rpm, 17 dBA (included),
Side fan(intake): 200x230x30mm, 900 rpm, 150 CFM(included)
Power Supply Standard ATX PS2 / EPS 12V (optional)
Optional Component Transparent side panel,
Fan bracket
Other Keep-out requirement for CPU cooler installation:,
At least 5.7 inch(145mm) separation between motherboard and the side panel of COSMOS S


The Cooler Master COSMOS S came packaged in a large double-walled box.  Like virtually every other case, the COSMOS S chassis itself is secured in position in the box by large pieces of Styrofoam and the entire case is wrapped in a plastic bag.  In addition, the chassis is tucked into a reusable cloth sack, to prevent dust from getting onto the chassis during shipping.  The high-quality cloth sack certainly added to the product's out-of-the-box appeal.

Additional accessories for the case, like the power cord, wire ties, adhesive wire tie downs, screws, and the manual were secured inside the chassis itself.  The wire tie downs included with the COSMOS S were a nice touch, because they'll make it easier for users to manage the typical rat's nest of cables that reside inside a high-end PC, without having to make an additional purchase.

COSMOS S: Exterior

The Cooler Master COSMOS S' exterior is similar to the original COSMOS in form, but the finish, inputs, and ventilation scheme are all somewhat different.


Like the original COSMOS, the new S variant has what appear to be bar-like handles along both sides of its top and bottom edges.  And its general shape is like the original COSMOS as well.  The COSMOS S, however, has a new titanium and glossy black finish that really stands out.  The side and top panels are easily removable, literally at the touch of a finger - press the latch release for either side and the panels pop right off.  And the top vents can be slid off to access the fans for cleaning, etc.


There are four USB ports, a microphone and headphone jack, a Firewire port, and an eSATA port on the top of the COSOS S' front bezel, that can be hidden away by a sliding door. Just below the port cluster is a touch sensitive power button that senses when a finger has touched it with no moving parts.  The switch and the ports are all lit from behind with an array of red LEDs, which makes them easy to spot, even in low light. 


The numerous drive bays on the front of the COSMOS S are also easily accessible thanks to an innovative locking mechanism.  There are hinged doors on either side of the case, that swing out of the way when released.  Then you can simply snap off the bay covers.  In total there are 10 drive bays on the COSMOS S, with the four lowest bays visible from the front reserved for hard drives and an intake fan.

COSMOS S: Interior

The Cooler Master COSMOS S' interior also has a number of interesting features designed to ease the installation process, improve cooling performance, and reduce the case's acoustic profile.


The most notable internal feature is the COSMOS S' vast real estate.  This chassis can accommodate just about any graphics card / motherboard combination you can throw at it, with room to spare, eATX, ATX, CEB, whatever.  As you'll see a little later, we actually assembled an Intel Skulltrail rig in this case and the motherboard still has a few inches to spare between it and the drive bays.

The COSMOS S includes simple push button locking mechanisms for holding optical drives, or any other 5.25" device in place.  The PSU mounts at the bottom of the chassis, which can be a problem in some cases due to restricted air-flow and debris getting sucked into the PSU.  But with the COSMOS S, because the chassis is lifted off of the ground, and there is an adequate vent with a filter beneath the PSU mounting area, it works well and helps quiet down a system by putting the PSU fan as far away from the user as possible.


The case includes three 120mm internal case fans (front, rear, and top), but there are location for an additional three fans should you need to improve airflow within the system.  The side panel houses a massive 250mm intake fan that blows across the motherboard, and cools the entire system.  Also note the built-in liquid cooling accomodations on the rear, which consist of a pair of cut outs for tubing.

Another feature that also improves the COSMOS S' acoustic profile is its 4-in-3 hard drive mounting bracket.  The bracket takes up three of the external drive bays and an holds four hard drives - hence 4-in-3.  The cage is outfitted with rubber grommets that isolate the cage from the chassis to prevent unwanted hard drive vibrations.  We should also note that an intake fan blows air right across the hard drives, to keep them nice and cool.

Installation and Usage

Installing our components into the Cooler Master COSMOS S was quick and easy thanks to its innovative design, but there were a few areas that could use a little improvement.

Mounting the motherboard went off without a hitch.  There is so much room in the case, and it includes a template that outlines where stand offs should be installed for every type of compatible motherboard, that there's almost no way to make a mistake.  Mounting optical drives was also easy thanks to the push button locking mechanisms, but we felt they didn't hold the drives in place tight enough.  With a disc inserted and spinning at full speed, the drives would most certainly vibrate, so we opted to install standard mounting screws as well.

Cooler Master COSMOS S with Intel's Skulltrail Platform

The PSU installation was also a snap and didn't pose any problems whatsoever.  The 4-in-3 hard drive dock took a little effort to remove, however.  Once removed, mounting drives is painless, but the cage does need to be perfectly lined up and jostled a bit to get back into place.  As far as installation goes, the COSMOS S is one of the better chassis we have ever worked with.  There is just so much room and things are laid out so well, it's hard not to like it.  Even with a full Skulltrail system complete with a GeForce 8800 Ultra, three hard drives, and two optical drives, the COSMOS S seems almost empty.

Once everything was installed and assembled, using the COSMOS S was generally a very good experience.  The top-mounted ports are in an excellent position and easy to access.  The cooling fans are very quiet and unobtrusive, and all of the system's components ran cool.  The only issues we have are related to the power buttons and LEDs.  After a few days, the LEDs lighting the USB ports died for no apparent reason.  And the power button is so sensitive that it's easy to accidentally touch it when plugging in a USB or other device into the top ports, which will shut down the system.  It definitely takes some getting used to.  We also would prefer the case include a reset switch, which it unfortunately does not.

Summary and Conclusion

Evaluation Summary: The Cooler Master COSMOS S excels in a number of key areas.  First off, there is simply so much room within this chassis that installing virtually any hardware combo will not be an issue.  The open accommodations also make it easy to work within the case, which is another plus.  The layout of the I/O ports is also very good, the cooling fans are quiet and perform well, and mounting drives is quick and easy too.  The only areas that could use some improvement are related to the push-button optical drive locking mechanisms, which could be tighter, and the power button, which is overly sensitive.

At about $250, the Cooler Master COSMOS S is not an inexpensive proposition.  That's a lot of coin to spend on a PC chassis that doesn't include a power supply.  But given this case's innovative features, good looks, and spacious interior, we can't help but like it.  Having built countless systems over the years, in numerous different enclosures, we're comfortable saying the COSMOS S is one of the best we have ever worked with.  Is it perfect?  No.  But we have yet to encounter the perfect PC chassis.  But the Cooler Master COSMOS S does come very close.  We're sure some of you will be put off by this case's aggressive looks, but we like it.

If you're in the market for a high-end full tower case, do yourself a favor and look into the COSMOS S.  It is not the least expensive case available, but we're confident it will stick with you through numerous upgrade cycles.  Over the long haul, the $250 investment is well worth it in our opinion.  This is a high quality chassis worthy of any power user's consideration.  Due to its innovative features, good looks, and roomy interior, we're giving the Cooler Master COSMOS S an Editor's Choice award.  If I was buying a new enclosure for myself today, this would be it.

  • Great Internal Layout
  • Quiet Fans
  • Top Notch Cooling
  • Good Looks
  • No Reset Switch
  • 'Touchy' Power Button
  • LEDs died

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