December 07, 2013

Cooler Master HAF Stacker 935 - The First Stackable "Mod-Tower"

By: Low Chern Lin

As a leading manufacturer in CPU coolers, PC towers/chassis/case and more, Cooler Master is a very familiar name to almost every PC users. Among their product line, the HAF series PC cases is an all time favorite. With its impressive high airflow design, modular HDD bay and more features along with all the excellent feedback along the way, the HAF series is definitely something worth to invest for.

In this review and unboxing, we will taking a good view in Cooler Master's latest product in the HAF series product line - the HAF Stacker. Claimed to be the world's first, the HAF Stacker offers a new level of exploration for the end users to build a rig with HAF Stacker to their liking. Priced at 559 Malaysian Ringgit and will soon be available in the Malaysian market, will this new HAF Stacker with its boasted innovative design be a worth to invest for? We'll find in out soon enough after the review.


Warranty2 Years from Cooler Master
Dimension235mm x 719mm  578mm
Motherboard Supportextended ATX, ATX, mATX, ITX (915R)
Expansion Slots8+1 and 2 (915R)
TypeMid Tower
MaterialSteel, Plastic
Drive Bays5.25" : 3 + 1 (915R)
3.5" :  9 ( 3 x modular cage )
2.5": 9 (Converted), 1 (Motherboard Tray) + 3 (915R)
Cooling Option
Top: 120mm x 2 

Front: 120mm x 2 / 92mm x 1 
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)
Front I/OUSB 3.0 Ports
x USB 2.0 Ports
x Speaker/ headphone
x Microphone
Power SupplyNot included


Million thanks to Cooler Master Malaysia for making this review possible, couldn't have done it without their great support. And now let us have a quick view on the packaging of th HAF Stacker, very simple yet stylish design we have here.  *The straps and edge protector are not included during purchase*

Inside the box, the HAF Stacker is protected by these polystyrene which absorbs shock to minimize damage to the case if anything unpleasant happened during transportation. And of course, the manuals are included as well, a very helpful guide to those who just getting started.

Quick view on the HAF 915R 

First out of the box is this miniature HAF 915R, which is the top of the HAF Stacker as seen on the box.

And let us now look at the side panels, anyone sees a slot for a 360mm radiator here? By removing the screws of the dust filters on the side panel, you'll have slot for the 360mm radiator. If you're wondering how could it be possible when the space available is so limited by just looking at it, your answer lies within the picture below.

The 4 holes and large rubber grommet at the bottom part of the HAF 915R. This is where your creativity takes place, it's not necessary that you need to have a system in the HAF 915R - you can make it as an additional slot as expansion for mounting radiators aka radiator box or having your HDD mounted here instead of being inside the main body HAF 925. 

From the top view, you can clearly see why the HAF series boasts to have extremely high airflow.
Imagine the amount of air going in and out of the case through these tiny holes.

Surprise surprise! You can remove the top panel by unscrewing the screws at the side of the top panel.

After removing the top panel, we can clearly see that the exposed rail system - Cooler Master's patent pending rail system that allows you to easily combine and remove the HAF Stacker with ease. 

And of course, something which must not be missed out is where to mount your motherboard in this case. The 4 spacers around the rubber grommet is where will your motherboard be placed and yes, you can only fit an ITX motherboard in it.

From the rear view of the HAF 915R itself, we can imagine how will a system being setup in it. Power Supply placed above the motherboard, 2 extra expansion slot for graphics card and maybe a sound card can be installed in the HAF 915R as well.

Quick view on the HAF 925

Up next is the HAF 925, which is the main body of the HAF Stacker. The front panel comes with a neatly aligned power button, audio jacks and both USB 2.0 and USB 3.0 ports.

Sexy looking Cooler Master logo on the front mesh, does this not tempted you? Do aware that this is not a power on switch, the real switch is at the same place along with the IO ports in the front panel.

The top view of the HAF 925, these slots allows you to install 3 cooling fans or perhaps a 360mm radiator on top while routing the tubes through the holes covered with rubber grommets at the rear view.

The picture above shows the holes covered by rubber grommets, which allows you to route your tubing for custom water cooling setup for an external mounted radiator.

Again we would highlight this, thumb screws! Always makes your life easier when you have one of these to tighten the side panel of your case instead of those traditional screws which requires a screw driver. Imagine when there's something going on and your side panel is secured with traditional screws but you can't find any screw drivers at the time. Always go for thumb screws for your own convenience.

Would you look at the size of that window, great to show the awesomeness of your rig to your friends. In addition, it's tinted for somehow, which I think is a good job to reduce the brightness of those over brighten LED which kills the look of an awesome setup during photo shooting session.

Besides of having a large window, the side panel itself is pretty sturdy I'd say, it only shows signs of minimal flex when it's being held horizontally.

And here's what's inside - lots and lots of rubber grommets to hide your cables at the edge of these cable routing holes. 

Good looking HAF Stacker wording at the side where your power supply unit will be installed.

There's 4 pieces of rubber base installed here, where the purpose is to reduce vibration caused by moving parts in the power supply which will generate noise. It also protect both power supply and the base of the case from being scratched as friction usually takes place when you mount a power supply here - it happened to my CM Storm Scout 2 years ago. I must say that Cooler Master has done a really good job in this part.

As usual where every manufacturer will do, a rear fan is included. Comes in handy to remove excessive heat from your system.

And now for the HDD bay, it's almost every HAF series casing from Cooler Master allows you to remove the HDD bay for various purposes - long graphics cards, mounting radiators and more. The pictures pretty much explains everything here, after removing the HDD bay, you can mount a 240mm radiator here but it's pretty limited to certain brands of Self Contained Liquid Coolers due to the fixed length of tubing.

There's plenty much of space here behind the motherboard tray for cable routing, but we would like to highlight this - there's a place where you can mount your SSD or 2.5" drive.  

here's another good approach taken by Cooler Master which we would like to highlight where removing the front panel has never been easier. Instead of using those traditional fitting like locks, Cooler Master takes a much simpler yet secure enough approach by having a simple snap lock which can easily be removed with an effortless push on it and no fear in breaking any of these locks.

Anyone knows what is the purpose of this small piece of cable being mounted here? It's attached to the front panel IO, so from our observation is that it acts as a grounding path for the IO panel which will probably prevent damage to your USB devices if there's a spike or surge going on. Nicely done I'd say.

And now with the bottom view, there's another 2 pieces of large rubber grommets here where you can probably mount another piece of HAF 915R where for various purposes. In short, you can basically mount as many HAF Stacker parts at will.

You can easily remove the bottom feel with a simple unscrew and slide, VERY convenient.

There's a removable dust filter at the bottom part where your power supply will be mounted to reduce dust intake to your power supply and at the same time allowing you to clean it at ease.

Accessories included is pretty much expected - all the screws you will need and cable ties for cable routing, except for the back IO panel cover and another piece of metal to cover your power supply slot if it's unused. 

HAF Stacker in action, quick and easy. Best of all, this is only one of the possible combination as recommended by Cooler Master. We'll show you some of our idea in the pictures below:

HAF 915R HTPC in action,
The HAF 925 Mid Tower unleashed!
But of course, to have either one of it, you will have to sacrifice the other part. So it's up to you to consider.
Meanwhile, check out our test configuration being setup in the pictures below!

As we have mentioned earlier, you can mount a radiator in front after removing the HDD bays, but it's limited to certain brands when it comes to Self Contained Liquid Cooler. The Corsair H100i is pretty much out of the league in this case. You can mount your HDD at the bottom stacked HAF 915R too, comes in handy when you need to install a radiator in front.

Adding two optional fans for either radiators or intake purpose will help in lowering some temperature.

And here's one of the purpose of the included power supply cover and back IO panel cover included.

Cable routing can be done at ease and you can have a SSD installed behind your motherboard tray.

Testing Method

Moving on with the testing methodology, the table above shows the components we will be using for this review. The test is carried out in a room with ambient temperature of 30ยบ  and the air intake is from the front 2 Scythe Gentle Typhoon, whilst the exhaust is rear fan included with the HAF Stacker. Stress test is done using Prime95 on CPU and FurMark on GPU and each stress test is conducted with side panel closed and opened  in a separated test where both CPU and GPU is  tested running under stock speed, following by some slight overclock on both . Each test took 15 minutes in average and the final result data collected from the test is presented in a graph and table as following:

From the data presentation above, we can see that the temperature performance is really impressive. For the Cooler Master Hyper 212 Evo being an average low cost performer, it is able to perform really well in the HAF Stacker although it is very obvious that the temperature can be easily beaten by any high end cooler, but the main focus here is that the air flow going in and out of the HAF Stacker. With the mesh front panel which allows fresh air to enter the case easily paired up with a pair of good fans that will gives you a lot of air flow, you wont even have to worry if there's any heat trapped in your case - but do expect more dust from it.


As one of the big cheese in the game, Cooler Master's attempt to penetrate the market with their newly innovated 'Mod-Tower' could possibly put a big change in the modding scene. Whether you're a modder, enthusiast or a home user, everyone can have fun changing the case to their needs - just like Lego pieces where countless and endless awesomeness born with one's creativity.

Before the end of the review, I would like to point out few things to take note of for anyone who now has the urge to get themselves a HAF Stacker:

- Modular units with great expandable headroom 
- Very convenient rail system which allows you to swap the case feet and top panel with ease
- Very big side panel window for rig showcase
- Removable HDD bays to allow 240mm radiators in the front bay
- Rubber grommets to cover up the holes for a neat and clean look
- Included accessories which allows you to cover the back panel IO and power supply slot if it's not in use
- 559 Malaysian Ringgit for all these features offered, we could say it's a bang for the buck

- Inserting thumb screws to the side panel holes is a little troublesome if you removed it from the side panel
- The case feet is made of plastic, so you will need to handle with care
- No additional case feet and top panel, if you decide to separate both system, it'll be a pain

The HAF Stacker from Cooler Master is indeed an excellent and innovative product which is my first time dealing with something so different yet so much element of surprises and I am truly over the moon with it. In short, The HAF Stacker from Cooler Master deserves a Gold award and Recommended award without any doubt.