Cooler Master ATCS 840 Aluminium ATX Case Page: 1
Introduction & Specs
As enthusiasts we have a lot to thank Cooler Master for. OK that may sound quite a bold statement, especially right at the start of the review, but unless you're sitting reading this review with your high-end PC sitting inside a beige plastic and steel box, it's true. Over the past ten years Cooler Master have been responsible for some of the biggest innovations in PC enclosure design and probably one of the best (for me at least) was the release of their ATCS range of aluminium cases. With models such as the ATCS-201, Black Widow and ATCS-4000, the ATCS name was about much more than an Advanced Thermal Cooling Solution, it was about understated styling, high quality materials and a total disregard for the budget.
However looks can only get you so far, and while the ATCS name certainly also suggested high-performance in the cooling department, many of the original ATCS cases featured little more than a few 80mm fans. With times changing and many manufacturers moving on to designs based around 120mm or larger fans, Cooler Master retired the ATCS brand and introduced a new beast to the market - the STC-T01 (or Stacker). Standing 21" tall with 11 fully vented drive bays and more space for fans than Wembely Stadium, the Stacker still to this day inspires the design of many cases by other manufacturers.
But even with great cases such as the Stacker and more recently Cosmos in their line-up, there have always been cries from the die-hard enthusiasts to bring back the ATCS range. For quite some time Cooler Master resisted, but today we're going to be rubbing our eyes in disbelief as we take a look at the first case to be born under the ATCS banner in over 5 years - the 840 'Full Tower Classic'. Let's hand it over to Cooler Master:
ATCS 840 constitutes a classic all-aluminum design that builds on the legacy of the original ATCS design. The aluminum construction not only allows for a lighter weight but complements the thermal design seamlessly with three 230mm fans, dedicated air duct for graphics card cooling and HDD cooling module for superb cooling.

Extra attention to make sure this elegantly design chassis is easy to install and maintain, which includes: slide-out motherboard tray along with easy CPU cooler-remove slot, tool-free HDD casing, patented finger pressing 5.25" drive to dust filter.

Lastly, it gives users the freedom to choose any components they desire, as it supports the latest standards such as E-ATX and dual PSUs.

Available Color Black / Silver
Dimension (W / H / D) (W) 243 x (H) 580 x (D) 630 mm
(W) 9.57 x (H) 22.83 x (D) 24.80 inch
Weight Net Weight: 13.25 kg (29.21 lb);
Gross Weight: 15.75 (34.72 lb)
Motherboards Micro-ATX / ATX / E-ATX
5.25" Drive Bay 6 Exposed (without the use of exposed 3.5" drive bay)
3.5" Drive Bay 6 Hidden
1 Exposed (converted from one 5.25" drive bay)
I/O Panel USB x 4,
IEEE 1394a x 1,
eSATA x 1,
Mic x 1,
Audio x 1
Cooling System Front : 230 x 30mm standard fan x 1, 700 RPM, 19 dBA (included)
Top: 230 x 30mm standard fan x 2,700 RPM, 19 dBA (included)
(can be swapped for three 120mm fans)
Rear: 120 x 25mm standard fan x 1, 1200 RPM, 17 dBA (included)
Bottom: 120mm (optional)
HDD Module: 120mm fan x 2 (optional)
External Air Duct: 120mm fan x 1 (optional)
Expansion Slots 7
Power Supply Dual Standard ATX PS2 / EPS 12V (optional)
Without wanting to spoil some of the surprises over the next few pages the ATCS 840 features three 230mm fans, a 120mm fan and further space for an additional two 120mm fans. This is a complete U-turn on the ATCS cases of yesteryear and positions the 840 as possibly the most well equipped (fan-wise) case on the market at the moment. Other features include a removable motherboard tray, tool-free hard disk insertion and dust filters. Cooler Master haven't at this stage mentioned how thick the aluminium used on the 840 is, but we'll find out for sure over the next page...

Cooler Master ATCS 840 Aluminium ATX Case Page: 2
Packaging & External Appearance
Packaging on the ATCS 840 is quite a standard affair with the case arriving inside a brown double-walled cardboard box. At the front of the box is a sketch-like graphic of the case sitting in front of two unicorns and a knight. Around the back is yet another image of the 840, but this time from a more technical perspective with the case being fully 'exploded' to give potential buyers a good idea of just how the case fits together. Overall the design is fairly minimalistic, which is quite fitting considering Cooler Master are marketing the 840 as a 'Classic' design.
Cooler Master ATCS 840 Box Front Cooler Master ATCS 840 Box Back
Cooler Master ATCS 840 Packaging Cooler Master ATCS 840 Accessories
Once inside the box you are presented with the ATCS 840 sealed inside a clear plastic bag. To be honest, we were half expecting the drawstring fabric bag used on the Cosmos S to make a reappearance here, but unfortunately the 840 receives no such treatment. Two polystyrene slabs protect the top and bottom of the case and prevent it from moving around during shipping. However, at the end of the day the fate of the case is ultimately still in the hands of the courier.
Jumping ahead of ourselves a few steps, Cooler Master have secured two accessory boxes inside the case. Included in these boxes you will find the usual assortment of screws and motherboard spacers, some sticky cable tidies, a 120mm fan grill, brackets for securing a triple radiator and the external air duct that we'll cover in detail a little later.
Cooler Master ATCS 840 Front Cooler Master ATCS 840 Front-Side
Starting around the side that you're most likely to see during every day use, the most striking feature about the ATCS 840 is most definitely it's width. Compared to the likes of Lian Li's V2010, the 840 comes in around 4cm wider, giving the case a rather 'beefy' appearance. A total of six 5.25" drive bays are on show at the front of the case with one serving a dual purpose as a 3.5" bay as well.
Interestingly the drive bay covers are not totally made from aluminium, and instead have a plastic construction with an aluminium faceplate. This may sound like a cost saving exercise, but has actually been done so that the bezels work with Cooler Master's patent pending quick release drive buttons. Furthermore this also prevents the problem of scratches that some aluminium drive bezels leave behind when removing them from your brand new case.
Cooler Master ATCS 840 Front Lower Cooler Master ATCS 840 Front Fan
Moving on to the lower half of the case we can see the aluminium face plate that left many of our forum-goers in two minds when the ATCS 840 was revealed to us a couple of months ago. While I personally quite like the way the plate breaks up what could have been a rather bland case design, the oversized silver Cooler Master logo looks extremely out of place on the black version of the 840 and would have been much better sprayed entirely black.
Removal of the plate to access the 240mm fan and filter placed behind is actually quite tricky and led to a few cringe-worthy moments. While the manual simply shows the face plate being pulled outwards away from the chassis, the plastic tabs used to hold the plate in position looked like they would snap at any minute. For a case of this class it would have been much nicer to see some kind of magnetic hinging system, or even something as simple as four screws.
Cooler Master ATCS 840 Side Cooler Master ATCS 840 Side
The side panels of the ATCS 840 are fairly standard and slide into place like the marjority of other standard cases. Once again it would have been nice to have a door mechanism like the Cosmos S or indeed the Lian Li 'V' series, but maybe we're asking a bit too much? The ATCS 840 also falls short of the Cosmos S when it comes to the thickness of the side panels. Whereas the Cosmos S is often applauded for its rigid 1.5mm thick aluminium panels, the ATCS 840 panels are actually quite flexable when detached from the case and we'd estimate them to be around 0.9mm thick

Neither of the panels feature any kind of additional cooling - be it vents or fans (Not that it's needed!!), and at the present time we're unsure if Cooler Master will be releasing any windowed panels.
Cooler Master ATCS 840 Top Cooler Master ATCS 840 Top Grill
The top of the ATCS 840 is simply jaw dropping. While most manufacturers are happy with simply placing a couple of 120mm fans at the top of their case, Cooler Master have taken things several steps further by kitting the ATCS 840 with two 230mm fans. This gives the ATCS name some real meaning and as we've already seen from the accessories box, the fitting of a triple (or 360mm) radiator is absolutely no problem either.
Cooler Master ATCS 840 Ports Cooler Master ATCS 840 Button
To match the aluminium face plate at the front of the 840, Cooler Master have designed a console style area at the top of the case which contains the power and reset switches along with a pop-up interface that provides access to four USB ports, a 1394 port, an eSATA port and microphone/headphone sockets. Everything here feels of the utmost quality, with the power switch and USB interface having little lateral movement.
 Continued over next page...

Cooler Master ATCS 840 Aluminium ATX Case Page: 3
External Appearance Continued...
Cleaning and removal of the 230mm fans is quite easy thanks to the slide-out grill that is secured into place with two thumbscrews. This is a huge bonus for those of us who are often forced to completely disassemble our systems when fans and radiators get clogged with dust. Replacing the grill after cleaning can be a tad tricky as it requires perfect lining up of the grill with two small rails at either side, but this is a small price to pay for a grill that doesn't vibrate when the system is powered on.
Cooler master ATCS 840 Fan Grill Cooler Master ATCS 840 Fan Grill Open
Cooler Master ATCS 840 Fans Cooler Master ATCS 840 Rad Mount
Placing the radiator mounting kit over the 230mm fan screw holes we can see just how the system would fit together with a 360mm radiator installed. It's a bit disappointing that Cooler Master opted to make the brackets from plastic rather than something a little more robust such as aluminium or steel, but the plastic does feel slightly reinforced and we doubt there will be any complaints of radiators snapping off.
Unfortunately we didn't have any radiators to hand to test measurements and fitting, but Cooler Master tell us that the ATCS will support the same radiators as the Cosmos S, which from our previous review are:
HWLabs BlackIce GT Stealth III
HWLabs BlackIce GT Xtreme III
HWLabs BlackIce Pro III
HWLabs BlackIce GT
Watercool HTSF 360
Aquacomputer Airplex Evo
Aquacomputer Airplex Pro
Alphacool NexXxoS Pro III
Magicool Aluminium 360
Magicool Xtreme 360 Radiator
Magicool Slim 360 Radiator
Swiftech MCR320 QP 360 - thanks mushikun!

Not Compatible:
Thermochill PA120.3
 Cooler Master ATCS 840 Rear Cooler Master ATCS 840 Top PSU
Cooler Master ATCS 840 Fan Cooler Master ATCS 840 PCI Area
Finishing up at the back end we can see that the ATCS 840 has space for two PSU's. Obviously adding a second PSU to the top of the case removes any chance of installing a radiator, but it's certainly nice to be given the option anyway. The top PSU blanking plate features two holes fitted with rubber grommits for feeding water tubing to the outside of the case should you want to mount a radiator externally.
Unfortunately Cooler Master couldn't fit another 230mm fan at the back of the case (haha), but we're sure if they'd been given the chance they would have done. Instead the main exhaust fan for the ATCS 840 is a rather standard 120mm complimented by a honeycomb grill that runs down the right hand side of the expansion slots.
 Cooler Master ATCS 840 PCI Vents Cooler Master ATCS 840 PCI Vent
Here we see the "External Air Duct" mounted to the PCI expansion slot area. The idea behind this system is to draw the hot air from devices such as graphics cards and the general system out the back of the case and redirect it sideways. This prevents hot air from 'bouncing' back into the case when it is pushed up against a wall and will hopefully help to keep system temperatures lower.

Cooler Master ATCS 840 Aluminium ATX Case Page: 4
Internal Layout
Sliding off the side panel the first thing you are greeted with are the two accessories boxes we opened up earlier in the review. These are accompanied by a large white sheet of card that covers the motherboard tray area offering useful information on where to place those motherboard spacers for mATX, ATX and E-ATX motherboards. Overall the internal area of the case looks fairly spacious and shares a similar layout to the popular Lian Li A70.
Cooler Master ATCS 840 Inside Cooler Master ATCS 840 Inside
Cooler Master have clearly been listening to enthusiasts and have not only made additional holes in the motherboard tray to assist in the tidy routing of cables, but have also placed a large rectangular cut-out towards the top-left of the tray where the CPU would normally sit on a standard ATX (single CPU) motherboard. This enables users of the ATCS 840 to install/remove CPU coolers and waterblocks that require 'hard mounting' with bolts and backing plates, without first having to remove the motherboard. Kudos Cooler Master!
Cooler Master ATCS 840 Bottom Cooler Master ATCS 840 HDD Area
At the bottom of the case are two 120mm fan grills with the one to the left providing ventilation for PSU's with downward-facing 120mm fans. In both instances the vents are protected with fan filters which is EXTREMELY important when drawing air up from dusty surfaces such as carpets. It's also good to see that Cooler Master have made the fan filters easy to remove by simply pulling a handle and sliding the filter tray out.
Although not so easy to make out, the picture above-right shows the hard disk bay complete with a bracket for mounting a further two 120mm fans. While we're sure that most people will be content with the huge 230mm fan keeping their hard disks cool, it's good to see that Cooler Master are giving users the option to turn the ATCS 840 into a true wind tunnel!
Cooler Master ATCS 840 Drive Bay Cooler Master ATCS 840 Quick Release
For easy insertion and removal of hard disks, Cooler Master have fitted plastic trays to each of the six bays. These act much like the caddy's found in server systems, but without the ability to 'hot-swap' drives due to the lack of an SATA backplane. While the cost of installing a backplane in the ATCS 840 would have been relatively high, this is something that Lian Li have done in their recent X2000 enclosure and in addition to giving users hot-swap functionality, it also allows drives to be installed/removed without needing to remove both side panels from the case.
Cooler Master ATCS 840 Motherboard Tray Cooler Master ATCS 840 Bearings
Last, but most certainly not least is the removable motherboard tray. This allows a good portion of the system to be constructed outside of the case and then slid back into position for the final few cables to be connected at the end. A common problem with removable trays on most cases is that tall CPU coolers often hinder the reinsertion of the motherboard due to the width of the case. However, as the ATCS 840 is just that little bit wider than your average enclosure, even some of the tallest coolers should fit in without any clearance issues.
As we can see from the image above-right, Cooler Master have also opted to use bearings along the tray rails. This makes removal and insertion much more pleasant and reduces the chance of any vibrations/rattle between the tray and the rails when the system is powered on.

Cooler Master ATCS 840 Aluminium ATX Case Page: 5
Test Setup & Results
While hardware such as graphics cards and power supplies are always extremely easy to test and the results they produce easily comparable, cases are a different animal all together. You can't (unfortunately) just install a copy of CaseMark06 on the machine and read back some numbers once it's done. Therefore, Overclock3D has a standard testing methodology and set of hardware that is used in times like this, so that we can at least get a rough feel for how the case performs.
CPU: Intel Core 2 Duo E8400 @ 4.0ghz (1.40v)
Graphics Card: ASUS HD 4870X2
Motherboard: Asus P5K3 Deluxe
Hard Drive: 1x Hitachi Deskstar 80GB 7K80 SATA2 7200RPM
CPU Heatsink: OCZ Vendetta II

Today we will be placing the Cooler Master ATCS 840 head-to-head with another similar sized case currently in our labs; the Lian Li v1010. To ensure that we didn't give either of the cases any unfair advantages only the stock fans were used during the testing. In addition to this, all fans were connected directly to a +12v molex to prevent any potential skew in the results from the motherboard trying to manage the fan speed.

Temperature readings for the CPU were taken using OCCT, GPU via ATITool and System / Hard Disk via digital thermal probe. While we fully understand that the results taken using software appications may not be entirely accurate, they serve only to display the comparitive differences between the two cases when tested under the same conditions.

At idle, the ATCS 840 is already showing its superior cooling performance by keeping each of the components at least 3°C cooler. It is worth mentioning at this point that despite each of the fans inside the 840 running at full speed (12v), the overall noise emmited from the case was lower than that of the V1010 and barely audible above the 4870x2 GPU cooler.

At load, little changes in terms of CPU and GPU temperatures, with the ATCS 840 still keeping things around 3°C cooler. However, while the system temperature inside the V1010 hits 41°C, the ATCS 840 manages to keep everything an impressive 6°C cooler at 35°C.

Cooler Master ATCS 840 Aluminium ATX Case Page: 6
Cooler Master ATCS 840 Black / SilverStarting with the basics, there is simply no denying that the ATCS 840 is one very good looking case. While some people have had their reservations about the shield-like plate on the front panel it is by no means a deal breaker, and from a personal standpoint I believe it to add character to what could have been an otherwise bland design. Other aesthetics such as the no-gimmick side panels and high quality power switches mounted atop the solid aluminium console all give the case a premium feel that picks up from where the ATCS series of yesteryear left off.
Moving on to cooling, it's instantly apparent that Cooler Master have designed the ATCS 840 with the aim of making it the best cooled case on the market. With three 230mm fans and a 120mm fan factory installed, the case is not only deadly silent but also has more airflow than the back-end of a Boeing 747. Water-cooling has also been catered for too, with the inclusion of brackets to convert the dual 230mm fan holes into a mount suitable for a wide range of triple radiators.
Finally, installing a system inside the ATCS 840 is a breeze thanks to its removable motherboard tray and well placed holes for routing cables. It would have been nice for Cooler Master to include an SATA backplane for easy connection of hard disks along with the ability to 'hot swap', but this comment belongs more on the wish list rather than as a negative about the case.
To sum things up, the ATCS 840 comes very close to being our dream case. Not only is it one of the coolest cases we've ever tested, but it's also one of the best looking. Expected to retail at around £200 when finally released in December, the 840 is at an acceptable price point for a case of its calibre and sits snugly between the likes of the Lian Li V1010 and PC-X500.
The Good
- Classic styling. Sexy yet simple.
- Quality workmanship.
- Quiet, yet extremely effective cooling via 230mm fans.
- Ability to install triple radiator with included brackets.
- Easy to remove filters on all fans.
- Removable motherboard tray and largely tool-less installation.
- Room for up to 3 additional 120mm fans to increase airflow further.

The Mediocre
- Side panels made from quite thin Aluminium
- Silver Cooler Master badge spoils appearance of black version.
- Front plate secured with plastic latches that feel prone to failure.
- Very low to ground. Fans at base of case could use more ground clearance.
The Bad
- Nothing to report.

The Wishlist
- Black interior. Enthusiasts like showing off the inside of their PC's just as much as the outside.
- Wheels. A case that draws air up from the floor needs more ground clearance.
- Screws not rivets. Not on every part of the case, but adding modularity to the Hard Disk rack would be a great start.
- Thicker Aluminium side panels.
- Less plastic. Replace catches and brackets with something more substantial.

Overclock3D Editors Choice Award

Thanks to Cooler Master for sending the ATCS 840 in for review. Discuss this review in our forums.