Building with the Define S

Readers of the Define 5 review will see few changes in the build process with this new enclosure, with the lack of any drive bays on the inside of the case being the obvious difference (though all drive bays were optionally removable with the Define R5).

A look at the Define S's wide-open internal layout

And here's where things get a lot different – not just from the R5 but from any enclosure I've encountered. All storage bays are mounted flush against the back wall of the enclosure.

While this has become commonplace for SSD mounts it's interesting to see 3.5" bays installed this way.


The drives are very easy to install with a single thumbscrew securing each tray, and all three 3.5" trays have rubber grommets to control vibration.

With a drive in place there is still plenty of clearance for cable routing, as the Define S has a generous amount of room behind the rear panel


This is what this case was built for, and there are so many options available with the Define S that it would take a massive effort to try testing and covering them all. For this build I opted for a simple 240mm AIO liquid CPU cooling solution and an air-cooled graphics card, but with this much internal room and plenty of fan mounts this would be an excellent choice for housing a custom loop.

The Define S includes toolless reservoir mounts and pre-drilled pump mounts

Fractal Design has an entire separate specifications section for the cooling support for this case:

Cooling system

Front: 3 – 120/140 mm fans (included is 1 Fractal Design Dynamic GP14 fan, 1000 RPM speed)
Rear: 1 – 120/140 mm fan (included is 1 Fractal Design Dynamic GP14 fan, 1000 RPM speed)
Top: 3 – 120/140 mm fan (not included) or 1 – 180 mm fan with 165mm hole spacing (not included)
Bottom: 1 – 120/140 mm fan (not included)
Side: 1 – 120/140 mm fan (not included)
Dust filters: Bottom and front intakes

Water cooling compatibility – Radiators

Front – 360, 280, 240, 140 and 120 mm radiators of all thicknesses
Top – 420, 360, 280, 240, 140 and 120 mm radiators. (A thickness limitation of 55mm for both radiator + fan applies on 420, 280 and 140 mm radiators)
Bottom – 120 mm radiator (Use of radiators in the bottom position limits the PSU length to 165 mm)
Rear – 120 or 140 mm radiator

Water cooling compatibility – Pumps

Pre-drilled holes on the bottom panel, supports many DDC and D5 variants

Water cooling compatibility – Reservoirs

Adjustable mounting brackets allow for almost any rectangular mounting screw pattern
Maximum distance between the mounting bracket screw positions: 350mm height / 80mm width

Quickly going over the space available in the Define S we'll first look up top, where removable panels (lined with insulation material) can be popped out to reveal a triple-fan opening supporting up to 420 mm radiators.

Inside the rear of the case a 140 mm fan is fitted from the factory, and a 120/140 mm radiator can of course be installed here if needed.

Next we have the bigger front area which supports up to 360 mm radiators. This is populated with a single 140 mm fan out of the box, and is the location I chose to mount my 240mm cooler.

Finishing the Build

The build in progress – man is there a lot of space in here!

Installation of the motherboard, graphics card, and power supply was as uneventful as one might imagine considering there is absolutely nothing hampering the build in any way inside this enclosure. The storage mounts on the back are likewise easy to use, and cable routing is dead simple with Fractal's awesome velco straps along the back returning from the R5. My overall impression when finishing the component installation was "wow is there a lot of empty space in here!" It's almost absurd how much space there really is, especially when your motherboard is only micro-ATX!

Next up, the completed build with the Define S plus noise and temperature results!

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