Cooler Master Cosmos II: Ultra Tower Case

Table of Contents

The Cooler Master Cosmos II is marketed as an ultra high-end, extremely well-built case with an almost complete feature-set designed to house the best and most of everything a PC enthusiast would desire. For US$349, it better.

January 3, 2012 by Lawrence Lee

Cooler Master Cosmos II
ATX Tower Case

The Cosmos was one of Cooler Master’s largest and most popular cases. Debuting in 2007, the 25″ tall behemoth was received warmly by PC enthusiasts and gamers with deep pockets and ample floor space. To ring in the new year, Cooler Master has released the sequel, the even bigger Cosmos II with an an initial MSRP of US$349. Yes, many would consider this an absurd amount, but the Cosmos II is a premium product reserved for those who want the best of everything — build quality, space, features, and ease of use. We recently reviewed a budget tower, the disappointing Raidmax Viper; Now let’s see what you can get for five times the price.

The box.

Obvious shipping damage.

Given the cost and size for the case, Cooler Master felt it necessary to wrap the box with additional cardboard but it proved to be futile in the end. The dimensions and weight of the package proved to be an obstacle for the courier, with one corner of the box taking a noticeable beating, bending inauspiciously inward. Upon inspection we found some damage but it was mostly at the bottom of the case where it would not affect its aesthetics and/or thermal/acoustic performance.

The Cosmos II.

The Cosmos II is simply put, a world-eater, larger in every respect than any case we’ve tested previously, occupying some 157 litres of space. Standing 27.7″ inches tall, it towers over the Antec Twelve Hundred by almost 5 inches, its 13.5″ waistline spans 4 inches wider than the In Win Dragon Rider, and its 26.1″ depth edges out the SilverStone Raven Two by 3/4 of an inch. The exterior is a mix of a aluminum, plastic, and mesh, but the steel interior is what constitutes most of the Cosmos II’s 47 lb bulk. With the case being both supremely massive and heavy, the handle bars at the top are actually a necessary feature as it would be incredibly difficult to lift otherwise.


The included accessories are a bit on a sparse side for an expensive, premium case. It ships with an 8-pin extension cable, PC speaker, radiator mounting brackets, keys for a pair of hotswappable external SATA bays, screws, and cable ties.

Specifications: Cooler Master Cosmos II
Available Color Black
Materials Appearance: Aluminum, Mesh, Plastic
Case body: Steel
Dimensions 344(W) x 704(H) x 664(D) mm, 157 litres
13.5(W) x 27.7(H) x 26.1(D) inch
Net Weight 21.5kg / 47.3 lb
5.25″ Drive Bay 3
3.5″ Drive Bay 13 (2 from X-docking, Mid cage for 5 HDDs, Bottom cage for 6 HDDs)
2.5″/3.5″ Drive Bay 11 (converted from 3.5″ bay)
I/O Panel USB 3.0 x 2, USB 2.0 x 4, E-SATA x 1, Audio In and Out
Expansion Slots 10+1
Cooling System Front: 200mm LED fan x 1 (converted from 120/140mm x 1)
Top: 120mm black fan x 1 (converted from 200mm fan x 1/ 140mm fan x 2 / 120mm fan x 3
Rear: 140mm fan x 1
Side: 120mm fan x 2 (optional)
HDD: 120mm fan x 3 (2 fans for bottom HDD / 1 fan for Mid. HDDs)
Power Supply ATX PS2 / EPS 12V
Maximum Compatibility CPU cooler height: 190mm/ 7.48 inch
GPU card length: 385mm/ 15.10 inch


The Cosmos II measures 34.4 x 70.4 x 66.4 cm or 13.5 x 27.7 x 26.1 inches (W x H x D) for a ridiculous total case volume of 160.8 L. The next most voluminous case we’ve reviewed is less than half the size, the In Win Dragon Rider at 76.8 L.

While more affordable enthusiast-class cases tend to adopt a manic attention-starved style, the Cosmos II keeps it fairly simple with a simple black paint job and some nice looking curves. The top of the case features a fine mesh grill for a possible three 120 mm fans on the interior ceiling.

Toward the front, a sliding cover pushes back to review backlit power and reset buttons and fan controls for four different sets of fans. There are three speeds available, each indicated by a different backlight color. There’s even a toggle switch for the blue LEDs of the included 200 mm front fan. Underneath are four USB 2.0 and two USB 3.0 ports as well as eSATA and audio connectors.

The external drive bays are hidden by a shield cover that slides downward, a nice feature for those annoyed by the limitations of front door hinges. There are five 5.25″ slots, but only three usable as two are occupied by hotswap SATA drive bays.

At the back of the case there’s a 140 mm exhaust fan, release latches for the side panels, and power supply installation frame. One of the reasons the Cosmos II is so tall is the presence of 10 expansion slots, enough to accommodate a four-way SLI/CrossFire configuration. There’s also a side-mounted slot that can be used with an extension cable if all the regular slots are physically occupied.

The same aluminum handle bars on the top are present at the bottom, but as it’s unlikely the case will ever be flipped upside-down, they’re effectively only used as feet. There’s a plastic “skirt” at the bottom that gives it the same curved look as the top. An air filter for the power supply fan can be pulled out from the rear for cleaning.

The damage caused by shipping was only visible at the bottom and mostly cosmetic.

Half of the braces on the inside of the left skirt were smashed, leaving behind some sharp plastic debris.


Though uncommonly large, the layout inside is fairly standard. The interior is spacious, wide enough to accommodate EATX and the various versions of XL-ATX motherboards, a ton of hard drives, as well as dual radiators, one on the ceiling, one on the floor.

There are three 3.5″ hard drive cages for a total of 11 drives. Two of the cages sit side by side next to the power supply in a separated compartment on the floor.

The Cosmos II is loaded with removable drive caddies all with dedicated cooling. The two cages at the bottom have two fans clipped on to a side-swinging door blowing over them. The expansion slot covers are held with thumbscrews so both drive and card installation are tool-less.

The case has an Antec P180-style power supply mount with a raised platform creating plenty of clearance.

The circuit board of the fan controller can be found on the ceiling next to the 5.25″ bays. There are eight fan headers with 3-pin extension cables included.

On the other side, we were disappointed to see not a single SATA backplane provided. For a US$350 case we would’ve expected to see at least a few. Cable management is well-taken care of with several large routing holes with grommets and a series of hooks for cable-ties underneath the large CPU heatsink cutout.

If unused, all three hard drive cages can be removed, though the top one requires some work. Taking out the bottom cages is simply a matter of removing the thumbscrews at the back and sliding them out. With the included brackets, one can mount a 240 mm radiator in their place.

The hotswap SATA hard drive bays are built as well as any aftermarket unit.


The Cosmos II shipped with four fans in total, a 140 mm model at the back, a 200 mm LED variant at the front, and two 120 mm units in the bottom compartment blowing over the hard drive cages near the case floor.

Removing one screw at the back allows the top cover to pull out, giving access to the ceiling fan placements. Three 120 mm fans can be used in total, mounted with standard fan screws. Alternatively, one can use two 140 mm or a single 200 mm fan.

As we only use one hard drive in our testing configuration, we took one of the fans from the floor compartment and swapped it to the top for additional exhaust.

The mesh filter at the front pulls away to reveal a 120 mm fan placement at the bottom and a 200 mm LED fan above it. In addition to a standard 3-pin power cable, the larger fan has a 2-pin cable that allows its LEDs to be toggled on/off by the fan controller.

The side panels are ridiculously thick, measuring about 22.2 mm wide on average. They are far sturdier than any previous case we’ve reviewed.

The side panels pull outward 90 degrees, but if you’d like more room to work, the bayonet mounting system allows you to simply lift them upward for complete removal.

On the other end, three steel barbs seal the panel with the rest of the chassis.

The right side panel has a removable compartment to access another dust filter. The left panel is identical, but also has a pair of additional 120 mm fan placements next to the video card area.


Assembling a system in the Cosmos II is a straight forward affair. Our test system consists of an Asus 790GX motherboard, a ZEROtherm FZ120 heatsink with a Nexus 120 mm fan, a WD Caviar hard drive and a Cooler Master 700W modular power supply.

A metal frame is installed onto the power supply’s exterior, so it can be slipped in from the rear of the chassis.

The hard drive trays have a semi-soft mounting system using rubber grommets and screws that push-in without turning.

Cabling is the biggest issue during assembly due to the eight fan extensions provided. There is also a second set of 2-pin cables to control LEDs, but the 200 mm LED model is the only fan included with the case that has LEDs and is also the only fan we know of in existence with a corresponding connector.

Fully assembled our system looks, as most would, rather barren. We measured CPU heatsink and graphics card clearance to be 18.9 cm and 38.4 cm respectively.

Taming all the fan cables is the biggest challenge at the back, but there is plenty of room to tie things down.

Clearance behind the motherboard tray is 21 mm, more than adequate.


System Configuration:

Measurement and Analysis Tools

System temperatures and noise levels were recorded with SpeedFan and GPU-Z
at idle and on load using CPUBurn (K7 setting) and FurMark, an OpenGL
benchmarking and stability testing utility.

Baseline Noise

The Cosmos II shipped with four fans in total, a 140 mm model at the back, a 200 mm LED variant at the front, and two 120 mm units in the bottom compartment blowing over the hard drive cages near the case floor. The case also has a dedicated 3-speed fan controller for up to 8 fans broken into 4 different groups. The front 200 mm fan had an odd quirk when powered via the controller, producing a noticeable thumping sound, particularly noticeable at low and medium speed where there was less turbulence to drown it out. When powered through normal means, it sounded fairly smooth and benign, similar to the other stock fans. Oddly enough, the fan had a similar measured noise level regardless of how we powered it, so we left it connected to the controller.

Stock Fan Noise Level
SPL @1m (dBA)
Front 20cm
Rear 14cm
Top (rear) 12cm*
Side (front) 12cm
Side (center) 12cm
(front, rear, top)
Measuring mic positioned 1m at diagonal angle left/front
of case.
*swapped from side

The side fans blowing over the drive cages on the case floor were the loudest, measuring 15 dBA@1m on low speed, up to 29~30 dBA@1m on high speed. The mounting system is likely partially responsible as the plastic tabs holding the fans allows them to rattle somewhat. As these fans were unneeded for our testing configuration, we removed both of them, using one of them as an exhaust on the case ceiling. The front, rear, and top fans produced a similar amount of noise to one another, and combined, generated approximately the same amount as a single side fan.

At medium speed, the Cosmos II’s rear, top, and front fans produced a noise level of 20 dBA@1m.

Test Results: 2 x ATI Radeon HD 4870 (CrossFireX)

2 x HD 4870 CrossFireX test system.

System Measurements
System State
CPU + GPU Load
System Fan Speeds
CPU Temp
SB Temp
HD Temp
GPU #1 Temp
GPU #1 Fan
1080 RPM
2350 RPM
2280 RPM
2290 RPM
GPU #2 Temp
GPU #2 Fan Speed
1000 RPM
1950 RPM
1880 RPM
1730 RPM
21 dBA
31~32 dBA
31~32 dBA
34 dBA
System Power
CPU fan set to 100% speed.
Ambient temperature: 23°C.

With the rear, top, and front fans set to low speed, our test system idled with reasonably good CPU and hard drive temperatures while the Southbridge was a bit hot at 56°C, an unfortunate consequence of being saddled beside two pieces of hot hardware. The HD 4870’s had high idle temperatures too as the stock coolers were spinning at only ~1000 RPM (they don’t typically ramp up when idle). At one meter’s distance, the noise level was a fairly quiet 21 dBA and the ticking of the front fan was not as audible with the rest of the system turned on.

Pushed on load, the medium speed setting seemed to work best, delivering slightly better temperatures and lower GPU fan speeds then the fans set to low. Best of all, the overall noise level didn’t change as the extra cooling allowed the GPU fans to slow down. The CPU and Southbridge temperatures rose by 13°C and 10°C respectively compared to idle, while the graphics card heated up to 90°C/85°C. In the this fan configuration, the noise level was measured at 31~32 dBA@1m, which, while loud by our standards, is quite good for our dual HD 4870 configuration. The ticking front fan also blended away into just a slight hum, having been more or less drowned out.

Our HD 4870 CrossFireX test system measured 21 dBA@1m when idle and 31~32 dBA@1m on load.


CrossFireX Configuration Comparison (Load)
Cooler Master Cosmos II
In Win Dragon Rider
In Win BUC
Antec P280
Fans Speeds
top, rear, front @med
top, rear, sides @9V, front @5V
top, rear, front @9V
top, rear, front @low
CPU Temp
SB Temp
HD Temp
GPU #1 Temp
GPU #1 Fan
2280 RPM
1890 RPM
2050 RPM
2440 RPM
GPU #2 Temp
GPU #2 Fan
1880 RPM
1680 RPM
1780 RPM
1950 RPM
32 dBA
32~33 dBA
32~33 dBA
CPU fan set to 100% speed.
All temperature results adjusted to 22°C ambient.

Though easily the most expensive case we’ve tested, from a pure performance standpoint, it fails to capture the crown, beaten out by the brute-force cooling system of the In Win Dragon Rider, with its huge left side fan, and right side fan blowing onto the back of the CPU. However it did edge out both the In Win BUC and Antec P280, producing similar thermal results but with a 1 dB improvement in noise level. This doesn’t sound like much, but its a significant amount with our hardware configuration.


These recordings were made with a high resolution, lab quality, digital recording
system inside SPCR’s own 11 dBA ambient anechoic chamber, then converted to
LAME 128kbps encoded MP3s. We’ve listened long and hard to ensure there is no
audible degradation from the original WAV files to these MP3s. They represent
a quick snapshot of what we heard during the review.

Each recording starts with ambient noise, then 10 second segments of product
at various states. For the most realistic results,
set the volume so that the starting ambient level is just barely audible, then
don’t change the volume setting again while comparing all the sound files.


Given its price-tag we were expecting a heck of the case and that’s exactly what we got. The Cosmos II’s mix of aluminum, steel, mesh, and plastic has been molded to give it a completely solid feel and a unique look that errs on the classy side rather than the garish. Aside from the thin plastic skirt that curves into the bottom, the build quality simply can’t be beat. The side panels alone are almost an inch thick at some points and have a bulletproof mounting system that can’t be misaligned. The size and weight is a huge turnoff however despite the presence of handle bars. It’s a beast to lug around when filled to the brim with gear, and even empty it’s a bit of a pain.

The good thing about its size is it can fit just about any hardware configuration you can imagine as it supports up to 10 fans, 13 x 3.5″ hard drives, 11 total expansion slots, and both a 240 mm and 360 mm radiator. It also has the usual features you’d expect in a premium case: front USB 3.0 and eSATA, tool-less installation for drives and expansion cards, removable fan filters, removable drive cages, excellent cable management, and a pair of external bays for hotswapping SATA hard drives. Cooler Master also went all out on the fan controller, an impressive piece of hardware that can adjust up to eight fans between three different speeds. It’s more capable than any stock solution we’ve seen, though a dial-based model with full control and the ability to turn fans off altogether would’ve been nice.

Aside from the physical aspects of the case, we have but two major complaints. The first concerns the included 200 mm blue LED intake fan which creates an annoying ticking noise when powered by the fan controller. It’s also the only included fan that has the 2-pin connector necessary to work with the fan controller’s LED toggle switch — the other seven 2-pin cables are completely useless, at least for the moment. It’s likely that a future line of Cooler Master LED fans will take advantage of this otherwise gimmicky feature. Our other big peeve is the complete lack of SATA backplanes for the internal hard drive bays. We would’ve guessed that some would be included given the expense of the case and its ample hard drive support. The external hotswap bays mitigate this omission somewhat, but it’s not a true substitute.

From a performance perspective, the Cosmos II did well, putting up similar numbers to the Antec P280 and other recently reviewed towers at a moderately lower noise level, but it didn’t wow us. While it is enormous and has extensive fan support, the Cosmos II’s cooling scheme is still rather conservative. This contrasts directly with the aggressive cooling strategy of the In Win Dragon Rider which remains the best performing tower we’ve tested (by a longshot). Some consider the Dragon Rider to be rather ridiculous looking but in our opinion, its aesthetics are at least as off-putting as the overall dimensions of the Cosmos II.

Of course we wouldn’t recommend a US$349 case to our general audience and the Cooler Master Cosmos II obviously isn’t being marketed as such. It’s an ultra high-end, extremely well built case with an almost complete feature-set designed to house the best and most of everything a PC enthusiast would desire. The cost can hardly been seen as extravagant compared to the price of three or four top-notch graphics cards, a Sandy Bridge Extreme CPU/motherboard, a custom water cooling system, and 8+ hard drives. If you’re planning a system without at least two of these four elements in mind, the Cosmos II simply isn’t worth the price, neither the hit to your bank account or the strain on your back.

Our thanks to Cooler Master for the Cosmos II case sample.

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Articles of Related Interest
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Fractal Design Define Mini MicroATX Tower
Antec P280: Performance One Refresh
Antec Solo II: The Legacy Lives On
SilverStone Temjin TJ08-E: MicroATX Evolved
Cooler Master Silencio 550 Quiet ATX Tower

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this article in the SPCR Forums.

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