Cooler Master HAF Stacker 935

Cooler Master is no stranger to breaking new ground in the wide world of computer peripherals having been in the business since 1992.  Their portfolio includes many OEM products, as well as consumer grade products.  Breaking the consumer products down, they manufacture products for budget minded users to the high end enthusiasts.  By looking at the market, they take risks by developing new products based on market trends.

Stacker 935

The HAF, or High Air Flow case design has been around since 2008, in 2013 they introduced a new model, the Stacker.  The Stacker is a stackable "mod-tower" that takes their experience with the HAF line and expands it to an easily expandable case.  At the heart of the Stacker line is a mid-tower along with two ITX cases, the 915R and 915F.  These can be combined in any configuration to meet the users need.  The basic combo model is the 935, commonly referred to as HAF-935-KWN1, which includes the mid-tower and the 915R.  Combined, the 935 is a very large system coming in at 9.255 X 28.8 X 22.75 (WxHxL), and includes a 2 year warranty; the Stacker 935 currently sells for $169.99 with free shipping at when it is in stock.

Stacker 935 Mid-Tower Full View

The mid-tower includes features that are commonly found on enthusiast grade mid-towers.  These features include liquid cooling compatibility, removable hard drive cages, tinted side window, SuperSpeed USB 3.0, filtered air intakes and more.

Stacker 915R Full View

The two 915 models are much smaller as they support only mini-ITX systems, and can be configured to support custom liquid cooling solutions or they can be configured to support up to 9 3.5" hard drives (additional hardware is necessary).  Between the two models of 915, there is a slight difference; one has a Rear mounted power supply (HAF-915R-KKN1), while the other has a Front mounted power supply (HAF-915F-KKN1).  The 915 models are relatively small, measuring only 8.97 X 9.76 X 22.75 inches (WxHxL).  While the 915R is included with the 935, it is also available separately.  The smaller 915 models sell for $69.99 shipped at Amazon.

Cooler Master HAF Stacker 915 Features and Specifications:


Model HAF-935-KWN1
Color Black / Black
Material Bezel: Mesh/Polymer; Case body: Steel SGCC-t0.7
Dimension 235 x 719 x 578 mm / 9.25 x 28.8 x 22.75 inch
Weight 15.6 kg / 34.5 lbs (Net Weight)
M/B Type EATX, ATX, microATX, Mini-ITX (915R)
5.25" Drive Bay 3 + 1 (915R)
3.5" Drive Bay 9 (3 x modular cage)
SSD Bays 9 (converted), 1 (MB tray) + 3 (915R)
I/O Panel USB 3.0 x 2, USB x 2, Audio
Expansion Slots 8 + 1 and 2 (915R)
Cooling System Top: 120mm x 2
Front: 120mm x 2 / 92mm x 1 (included)
Rear: 140mm (included) / 120mm x 1
Side: 120mm x 6, 140mm x 4 (915R)
Radiators: 360mm x 2 / 280mm x 2 (Side); 140mm / 120mm x 1 (Rear)
Power Supply Standard ATX PS2 x 2
Rear / Bottom Mounted
Maximum Compatibility VGA card length: 354mm / 13.9 inch; 360mm / 14.17 inch
CPU cooler height: 180mm / 7 inch; 80mm / 3.15 inch
Warranty 2 years
UPC Code 884102025228

Retail Packaging

Stacker 935 Packaging

The Cooler Master HAF Stacker 935 is shipped in a plain brown box, which is extremely large, it measures 25.5 x 11.5 x 33.5 inches (LxWxH); not to mention the weight to ship it coming in pretty close to 39.25 pounds.

Stacker 935 Packaging Material

Opening the box, we find familiar packing material.  The case itself is packed in a soft foam bag, with hard Styrofoam blocks.

Stacker 935 Packaging Blocks

The Styrofoam blocks are a little unique for this case, as there are three of them that protects the Stacker 935.  When taken out of the box, it looks just like it would be stacked in the default configuration if the blocks and foam bags were removed.  Shipping a box of this size must have been a bit of a challenge for the shipper, some damage happened, no damage to the case though.  Several pieces of the Styrofoam blocks broke off in the lower left corner.

Stacker 935 Accessories

Since the Stacker 935 is essentially two cases, there are a large number of accessories; some of which are unusual due to the unique case design.  No specific user manual was included, it is available online, however a "How to Stack" sheet was.  In addition, there are ten cable ties, a blank motherboard I/O plate, four rubber anti-vibration standoffs, two side panel locks, fifteen brass motherboard standoffs, a standoff socket, eight long fan screws and a large selection of other screws.  In addition to the blank motherboard I/O plate, two other unusual accessories are the large metal plate, used to cover the power supply hole on the 915R if no power supply is installed, and a SATA power cable extension for three SATA devices.

Stacker 925 Mid-Tower External Impressions

Stacker 935 Mid-Tower Full View

With an all black chassis, the majority of the case is metal.  The exceptions are the edges on the front bezel, the feet and the stacking rails.  The left side of the case has a very large window to show off the components.

Stacker 935 Mid-Tower Front

The front of the mid-tower portion is fairly standard, with a wire mesh covering the majority of the front.  At the top is the usual front I/O cluster that includes the power button, headphone/microphone jack, two USB 2.0 and two SuperSpeed USB 3.0 ports; there is no reset button.  There are three 5.25 inch device bays below the I/O cluster.  The Cooler Master logo is on the bottom section of the case, rather than call out to be looked at, the logo is black to match the rest of the case.

Stacker 935 Window

The left side panel has a large tinted window that is raised a little from the metal side panel.  The panel is held in place by two thumbscrews, which are designed to stay with the panel rather than being removed. 

Stacker 935 Mid-Tower Back Panel

The back panel provides the usual items; three external liquid cooling grommeted holes, standard motherboard I/O key, a 120mm or 140mm (included) exhaust fan, eight plus one expansion ports, and finally a bottom mounted power supply.

Stacker 935 Bottom Filter

On the bottom of the case is a removable filter, that pulls out the back of the case below the power supply.

Stacker 935 Mid-Tower Rt Side Panel

The right side panel is plain, nothing happening here.  Like the left window panel, it is held in place by two thumbscrews and is easily removed with the handle.

Stacker 935 Mid-Tower Top

The Stacker 935 comes pre-configured to have the 915R stacked on the top.  As such, there is no top panel, rather it is open.  Along the sides are the rails used to mount the 915, which are removable should the 915 be mounted on the bottom.  If a 915 unit is not mounted on the top, the specifications state 2x 120mm fans can be mounted here.  Most likely a liquid cooling radiator could be mounted here as well.

Stacker 935 Mid-Tower Bottom

The bottom of the case we find two grommeted holes in the event that a 915 case is on the bottom.  In addition, we see the removable power supply filter.

Stacker 925 Mid-Tower Internal Impressions

Stacker 935 Mid-Tower Internal

Removing the side panel we can take a look at the interior.  The exterior color has continued internally.  On the motherboard tray we find four cable management holes that are protected by rubber grommets, and one that is not.  In addition there is a rather large CPU support bracket hole in the tray.  Cooler Master has included 15 brass standoffs, in addition to the two that are already installed.  Lots of room here as it supports up to EATX motherboards.

Stacker 935 Mid-Tower 5.25 Bays

The 5.25" drive bays are clearly marked how to operate them, flip a switch to either Lock or Open; very easy to use.

Stacker 935 Mid-Tower 3.5 Bays

The 3.5"  hard drive bay uses a tray design.  There are two of these bays, each one supports six hard drives.  The bays can be removed to allow for liquid cooling or extremely long video cards.

Stacker 935 3.5 Drive Tray

The hard drive trays support both 2.5" and 3.5" drives.  In addition, they pull apart to allow easy installation of 3.5" drives.

Stacker 935 Internal Bottom Panel

As seen from the exterior, the bottom panel includes the power supply intake and the two large holes.  In addition, to support the power supply, there are four standoffs with rubber to reduce vibration.


The nine vented expansion port covers are held in place by thumbscrews.  Otherwise there is not much to see here.

Stacker 935 Mid-Tower Back of MB Tray

Like most, the back of the motherboard tray is pretty uneventful.  From this side, the data and power connections will be done on the hard drives.  Below the CPU support bracket is a hidden 2.5 inch hard drive mount.  This allows for the six hard drives on the trays, and a seventh behind the motherboard tray.  There are a total of eleven cable tie positions, so routing the cables to the appropriate spot shouldn't be a problem.

Stacker 935 Mid-Tower Bezel Off

Removing the front bezel is a little tricky as it is held in place very securely by six clips that need to be released from inside the case.  Once it is removed we find a fairly normal case.  At the top is the front I/O cluster, which has a ground wire to the case.  The 5.25" device bays are ready for installation as there are no guards to be removed.  Below those bays are two locations for 120mm case fans, unfortunately none are included so be sure to pick up a couple if cooling will be done with air and not liquid cooling.  The bezel itself is actually covered by a filter, and a large honeycomb plastic support frame.  The 5.25" bay covers are easily removed from this side by squeezing a couple of latches together.

Stacker 915 External Impressions

Stacker 915R Full View

Following the same style as the 925 mid-tower portion of the Stacker 935, the 915 is solid black with a full mesh front.  A side window has been replaced by a mesh panel.  This portion of the Stacker 935 measures  8.97 X 9.76 X 22.75 inches (WxHxL).

Stacker 915 Front Bezel

The front of the 915 looks nearly identical to the mid-tower, just much smaller.  The 915R has a couple of small differences; first as it is smaller, the 3 5.25" device bays is gone, replaced by a single device bay.  Next, and probably the most important, there is no front I/O cluster, and no power button.  I have inquired with Cooler Master whether this is available to be purchased separately.

 Stacker 915 Side Panel

There are two side panels, that are identical, they are actually interchangeable.  The side panel is mostly a filter, as three 120mm or two 140mm fans will fit on each side. If you prefer liquid cooling, a large liquid cooling radiator will fit here.

Stacker 915R Back

The back panel has features we would expect to find on any case, they have just been arranged differently, and a little less.  There is a large power supply slot, as the 915R supports standard ATX power supplies.  Beneath the power supply is the motherboard I/O key, which leads to two PCI vented expansion slots.  

Stacker 915R Top Bezel

Continuing the High Air Flow design, the top panel is all mesh.  It is also removable, which we will see a little later.

Stacker 915 Bottom

While there is usually a filter on most enthusiast cases for the power supply, as the 915R is part of the Stacker line, there are five holes to pass cables through.  Four of the holes are smaller, and has rolled edges instead of a rubber grommet.  The larger hole, which will be covered by a motherboard (if one is installed), does have a rubber cable guard.

Stacker 915 Internal Impressions

Stacker 915R Internal View

The side panel is held in place by a single thumbscrew, which once removed the panel slides off easily.  Here we can see what the 915R offers.  By default, it has a single 5.25" device bay, and three 3.5" hard drive trays, a rather large amount of space for, then room for a Mini-ITX or DTX board.  As the height of the case is 9.76 inches, that doesn't leave a large amount of room for CPU coolers.  Between the two models of 915, the 915R has the rear mounted power supply, so the CPU cooler has a maximum height of 80mm or 3.14 inches, while the 915F has the front mounted power supply, leaving room for taller coolers up to 170mm or 6.7 inches.

Stacker 915R Drive Bays

The single 5.25" device bay is tool-less and uses the same style of latch that was seen in the mid-tower.  As for hard drives, the 915R supports three drives utilizing the same tray design as the mid-tower.

Stacker 915R MB Tray

Taken from the top down with the top removed, the motherboard tray is visible.  Supporting Mini-ITX and DTX boards, there isn't a lot of room.  From this point of view, we can see that the power supply will be directly over the CPU, as such the height of the CPU will be limited.  Again, keep this in mind when choosing components, Cooler Master lists in the specifications that a CPU cooler can not be any taller than 80mm in the 915R, however the 917F it can be 170mm.

Stacker 915R Top Bezel Off

The top bezel is removed by two screws on each side.  With it removed, the rails are visible.  These are the same rails as installed on the top of the mid-tower and are necessary if this is to be stacked anywhere other than the top.

Stacker 915R Front Bezel Off

Two clips hold the front bezel in place, which when removed reveals a 92mm intake fan, and the single 5.25" device bay.  Taking a close look at the area where we would expect to find the front I/O cluster, it is only a place holder.  It would be possible to remove this (by the two screws) and replace it with a proper front I/O cluster.

Stacker 935 Hardware Installation

925 Hardware Installation

Stacker 935 Full Build

If installing an ATX or Micro-ATX board, there is a large amount of room since the case supports E-ATX boards.  Cable routing is easily accomplished the the number of cable management holes in the tray.  There were no surprises during the install, everything went as intended.  The two pre-installed motherboard standoffs are notched to make it easier to install the motherboard.

Stacker 935 MB Space

While the case is technically a Mid-Tower, it can support the E-ATX motherboards, so it is fairly long.  Once an ATX motherboard is installed, there is 4.5 inches of space between the edge of the motherboard and drive cage.  So video cards up to 14 inches in length should have no issues, if your video card is larger than that, the removable 3.5" hard drive cages will allow for much longer video cards.

Stacker 935 Back of Tray

Now  this is a large CPU support bracket hole, there is more than enough room to support any position of the CPU.  The hidden 2.5" drive fits nicely behind the tray, it's area is slightly raised so that gives a little extra room to connect cables.  Installing the drive is easy, slide one side onto the pegs, and use the included screws to secure it.  Cable routing wasn't fully complete at this point, however installing the side panel didn't require any additional force to get it to slide into place.

Stacker 935 Window View

 Once last look at the completed build before we take a look at the 915R example build.  The extra large window allows almost the entire interior to be visible through the tinted window.  With the front edge of the window being raised and it tapering towards the back of the case it gives it a nice look and feel.

915R Hardware Installation

The 915R can do multiple jobs, as either a cooling device, storage bay, and even a Mini-ITX system.  Even though there is no front I/O cluster, a Mini-ITX system will be installed in the 915R to give an idea how it can be done.

Stacker 915R Left Side

With the right side panel off, the hard drives are visible, and the Gigabyte HD7870 video card that is installed in the single PCI-E slot.  Plenty of room for even the longest of video cards.

Stacker 915R Right Side

Not many options for cable routing, however with cable ties it could look much nicer than this mess of cables.  There is enough room between the Mini-ITX board and the hard drive cage, where another cage could be installed, or place three cages in the 915 for even more storage space.

Stacker 915R MB Tray Hole

Removing the rubber grommet from the bottom of the 915R, there is no sign of the CPU cooler support bracket, make sure you install the one  you want before installing the motherboard. 

Stacker 935 Stacking

Cooler Master  has a nice micro-site that goes over what the Stacker is capable of, and sample configurations.  We pulled a few of these sample configurations to provide a few additional options to the standard layout.  In reality, the stacking options are only limited by your imagination and how stable you keep it.  The taller it goes, the more potential it has to tip over, just a small word of warning.

Stacker Vendor Sample Builds

One of the examples is to purchase the 915 series cases separately, and stack those as needed.  This is a great option for those with multiple Mini-ITX systems.  There is always the standard configuration of the 935, or you could purchase the 935 and another 915.  The mid-tower of the 935 is not available for purchase by iteself.

Stacker 935 Dual System

Stacked on top of each other with a system built in each case we can see how it would look.  Only one power supply was available for installation, so it was moved from the mini-ITX 915R case and installed int he mid-tower 925 case. 

Stacker 935 Mid-Tower Top Bezel

As the cases are designed to be stacked, the top bezel of the 915 fits nicely on the mid-tower portion.  This gives it a finished look should it be placed at the top of the stack.

Stacker 935 with 915R at Bottom

Like with the top bezel, the case feet are removed by two simple screws, and reattached the same way.  Stacked either way, the Stacker 935 looks great!

Stacker 935 Slide

Stacking of the case is extremely simple, once the desired layout is decided on, simply place them on top of each other.  The top case needs to be positioned towards the back of the lower case, then slide it forward.  Once it latches into place, the two screws that secure the top panel or the feet, are also used to secure the two cases together.  While not necessary if they are not going to be moved, it is recommended to secure them together for safety.

[youtube width="640" height="480"][/youtube]

Just in case there was concern about how easy the Stacker 935 is to stack, here is a quick video showing how easy the go together.  Please forgive the poor quality of the video, as we are just now starting to do more videos with our reviews.


Final Thoughts and Conclusions

When completed the Stacker 935 is an incredible system to look at.  On one hand, you have a single system with monster storage or nice large area for liquid cooling.  On the other hand,  you have two complete systems in one stacked case in the configuration of your choice.

Stacker 935

Everything installs easily in either case, with cable routing being a breeze thanks to the cable management holes.  The hard drive tray system is a nice change to the previous style of trays, they slide apart to make installing the hard drives easy and can also accommodate 2.5" drives using screws.  Finally, the installation of 5.25" devices is well thought out with the switch design to lock them in place.

When put together, the Stacker 935 is extremely large at 9.255 X 28.8 X 22.75 (WxHxL), it is a lot of case for the price which is currently at $169.99 shipped at with a 2 year warranty from Cooler Master.

There were a couple of downsides that I wasn't expecting when I originally looked at the Stacker 935.  I typically use air cooling for my systems, so when the mid-tower was found to only have the one exhaust fan, I was a little disappointed.  Although adding fans is extremely simple.  While we are discussing the lack of front fans, we can also discuss the front filter's requirements of removing the front bezel to be cleaned while the power supply filter is easily removed for cleaning.

The next downside came when I was building the two systems.  This would be a perfect system for my environment since I have two systems, one for work and one for gaming.  With the Stacker 935 I could save space.  Sadly, there is no way to control the power in the 915R series.  Cooler Master is aware of this and is preparing to release accessories, in 1st quarter of 2014, to allow users to add a power switch and front USB ports on the 915R.  In the mean time, it can be used as a storage box or external cooling solution.

Stacker 935 Side by Side


When everything is taken into account, the issues I had with the Stacker 935 are minimal, and will depend greatly on the individual needs.  The build quality is top notch, it has features that enthusiasts and modders want in a case; support for SSD, multiple long video card, large CPU cooler support, and easy cable management.

innovation award

Legit Bottom Line: While we only looked at one possible configuration, how the Stacker 935 is used will depend on the situation.  This is an incredible choice for people with multiple systems, massive storage or custom designed liquid cooling systems.  You can't go wrong with the Stacker system if it fits your need.