Fractal Define C Review: Logical & Quiet

By Published March 27, 2017 at 2:48 pm

Additional Info

  • Component: Case
  • Awards: Quality Build
  • Original MSRP: 90
  • Manufacturer: Fractal Design

In direct competition with the Be Quiet! Pure Base 600 ($90) we reviewed recently is the Fractal Define C, a compact ATX mid tower with an emphasis on noise suppression. The Fractal Define C is a relatively new launch from Fractal Design, sticking to the highly competitive ~$90 mid-tower market. Fractal’s Define C ships in micro-ATX (“Define Mini C”) and ATX form factor versions, the latter of which is on the bench today.

Our Fractal Define C review looks at the ATX-sized enclosure, taking thermals to task and testing for noise emissions in the company’s newest box. Fractal’s immediate competition at this price-point comes from the Be Quiet! Pure Base 600, NZXT S340 non-Elite, and the Corsair 400Q and 400C.

Fractal Define C Case Specs

Form Factor Mid-Tower
Mobo Support ATX, micro ATX, ITX
Dimensions 399 x 210 x 453mm (L x W x H) incl. feet
Weight 6.8kg (7.4 non-windowed)

2 x USB 3.0

3.5mm audio in/out

Expansion & Bays

7 expansion slots

2 x 3.5”/2.5” drive bays

3 x dedicated 2.5” mounts


Front: 3 x 120mm (1 incl.) or 2 x 140mm fans

Rear: 1 x 120mm (1 incl.)

Top: 2 x 120/140mm fans

Bottom: 1 x 120mm fan

Front: 360/280/240/140/120mm radiator, max width 144mm

Top: 240/120mm radiator, max mobo component (RAM) height 40mm

Rear: 120mm radiator, max width 125mm

MSRP $90

Build Quality

Building in in the Define C ($90) was easier than it had any right to be. First impressions were good, as the side panels smoothly hinge away from the body of the case and fit securely without uneven gaps, even with bundled cables pushing them out. Hopefully this means the era of side panels held in place by tiny, fragile metal tabs is coming to an end. Looks are extremely plain: the whole case is made of plastic and matte-black steel (~1mm thick internally), but construction is good and the materials completely fit the price. The only issue we encountered was a broken wire that disabled the HDD LED, but that’s theoretically a one-off shipping or manufacturing defect. The side window is simple acrylic and offers an unobstructed view of the internals, excluding what’s covered by the shroud.

The PSU and drive cage are completely hidden by a shroud that covers the entire bottom of the case, reminiscent of the NZXT S340, but with a notable improvement: a section at the front of the shroud can be popped out, allowing the drive cage to be removed and replaced with a 120mm bottom intake fan or a radiator that covers the full height of the case (or both). More realistically, a single 3.5” drive could be mounted instead of the drive cage and a 120mm fan could be installed in the front of the case to cool it. Airflow continues to the rear of the shroud, where ventilation holes allow radiant heat or front intake (if the bottom fan is installed) to escape the shroud area. This isn’t particularly useful, seeing as the PSU is a closed unit and should intake through the bottom, but would help when a bottom front fan is installed.



This cutout means that the Define C boasts support for a massive 360mm radiator on the front intake, although that doesn’t seem like an ideal configuration. Still, combined with the more easily usable 240mm mount at the top (when the “ModuVent” cover is removed), radiator capacity is impressively high for such a small case. The lack of any drive bays in the main chamber of the case means that front intake fans point directly through hot components towards the rear exhaust, although the two 120mm fans included aren’t going to break any records (more on that in the thermal testing section). Anywhere that there’s space for a fan mount, there is one, and all intakes are covered by two very large and sturdy filters.

Space is limited in such a compact case, and installing the cooler would probably have been the hardest part if we didn’t leave it permanently installed for test consistency. Get the cooler mounted first. It was a little difficult to wrangle the board in with MSI’s 15cm-ish heatsink jutting out, but there’s generous clearance on every side of the board.

Function Focused

In their web page for the Define C, Fractal Design says:

“So many cases on the market today are made to be all things to all people. However, for many this results in a chassis full of empty bays, unused mounts and excess bulk. Created for those who demand a flexible platform for a powerful ATX build that wastes no space, the Define C is the perfect solution to satisfy this balance of capacity and efficiency.”

Normally, that could be dismissed as standard marketing exaggeration. And to some extent, it is -- but the Define C does notably lack optical drive bays, supports only two 3.5” bays, and permits removable SSD mounts. This really is a case that trims all the fat and aims for a specific audience, which is why it has so much room despite its small footprint.


The lack of optical drive support means that the case can be almost as short as the width of the motherboard, but larger GPUs (like the GTX 1080 Gaming X we use) require a couple inches of additional clearance. This space isn’t wasted, but is instead used for a cable channel at the front of the case similar to the S340’s. Unlike the S340’s, though, this channel is sealed off from the inside of the case rather than covered with a metal cable management bar. Even without NZXT’s acclaimed cable management bar, the Define C was incredibly easy to manage: if we’d wanted to, we could have fit every single cable into this 35mm deep channel, but since there was also 15mm of space everywhere else, we didn’t need to bother. Rubber grommets along the side of the cable channel are angled towards the motherboard, which minimizes bending of SATA and other cables. Rubber grommets along the top of the motherboard are more unusual, but are a welcome addition given the number of motherboards that have a power header there.

Case Test Methodology

We tested using our new Skylake case test bench, detailed in the table below. This particular configuration is brand new with the launch of the 570X & 270R. Results on this test platform cannot be compared to previous case benchmark results, as the platform has completely changed.

Conducting thermal tests requires careful measurement of temperatures in the surrounding environment. We control for ambient by constantly measuring temperatures with thermocouples and laser readers. We then produce charts using a Delta T(emperature) over Ambient value. This value subtracts the thermo-logged ambient value from the measured diode temperatures, producing a delta report of thermals. AIDA64 is used for logging thermals of silicon components, including the GPU diode.

All case fans are manually configured to their maximum throughput using BIOS, then we configure to an RPM closer to 1050 for a universal "quiet" testing. If a fan controller is present, we opt-in and test on multiple settings. This forces testing of case fan performance in addition to the case's air channeling and airstream design. This also ensures minimal variance when testing, as automatically controlled fan speeds can reduce reliability of benchmarking. The CPU fan is set to 1100RPM (constant) for consistency, and the CPU is overclocked to 4.4GHz with a vCore of 1.272V (constant). C-States and power saving states are disabled.

  Component Courtesy Of Price
Video Card MSI GTX 1080 Gaming X (OC Mode) MSI $640
CPU Intel i7-6700K @ 4.4GHz GamersNexus $300
CPU Cooler MSI Core Frozr L MSI TBD
Motherboard MSI Z170A Gaming M7 MSI $180
Memory Corsair Vengeance LED 32GB 3200MHz Corsair $200
SSD Samsung 850 EVO 120GB Samsung N/A
PSU Corsair RM650x Corsair $100
Case This is what we're testing! - -

The video card is configured to run at 55% fan speed at all times.

Prior to load testing, we collect idle temperature results for ten minutes to determine the unloaded cooling performance of a case's fans and air channels. Thermal benchmarking is conducted for 1400 seconds (23 minutes), a period we've determined sufficient for achieving equilibrium. The over-time data is aggregated and will occasionally be compiled into charts, if interesting or relevant. The equilibrium performance is averaged to create the below charts.

Load testing is conducted using Prime95 LFFTs and Kombustor “FurMark” stress testing simultaneously. Testing is completely automated using in-house scripting, and executes with perfect accuracy on every run.

We recently validated our test methodology using a thermal chamber, finding our approach to be nearly perfectly accurate. Learn more here.


At $90, the Define C competes directly with ATX mid-towers we’ve previously reviewed, like the Corsair 400C and the Be Quiet! Pure Base 600, as well as the cheaper but similar NZXT S340. One wrinkle in potential comparisons is that we’re reviewing the Define C with a side window: since it still has acoustic padding on three of its six sides, its intentions are somewhere between the 400C (windowed), the 400Q (quiet), and the Pure Base 600 (very quiet). The two included 120mm fans are installed in nearly the exact same orientation that the 600’s were, and it may be the most valid direct comparison for both thermal and acoustic tests. Case fans were at max RPM for all tests.

We performed tests with the ModuVent cover on and off. The ModuVent™ (not sarcasm, it’s really trademarked) is a section at the top of the case that can be removed, just like the Pure Base 600. Unlike the 600, a dust filter can be stuck over the hole with magnets, and it’s easy to swap out the cover while the system is running.

CPU Temperatures


CPU dT hit 55.8C with the top open and 55.7C with the top closed, which is effectively identical. The cooler we currently use for case tests is oriented so that it pulls air from the front of the case and exhaust is pulled out the rear, leaving no opportunity for air to travel upwards and escape. The vent at the top of the case is nice, but there’s no reason to have it open unless a radiator or exhaust fans are installed there.

These CPU temperatures are okay, but not incredible compared to our other reviews. The Bitfenix Shogun with an additional 140mm fan and the S340 Elite at its maximum RPM scored similarly, but neither were cooling champions (Steve was particularly critical of the Elite). The front intake fan is responsible for aiming air at both the CPU and the GPU, and a few degrees of improvement could be expected from adding another fan and rearranging the airflow. Still, the default fan arrangement is identical to the Pure Base 600’s, which got more than 10 degrees warmer with its tiny air intakes.

GPU Temperatures


The downfall of cases with full shrouds is poor GPU temperatures. There was a slight improvement in GPU dT with the top open, but it was still less than 1 degree, and therefore not worth the extra dust without a radiator installed. 57.4 Celsius dT with the top open at maximum case fan RPM makes our GPU in the Define C significantly warmer than in the S340 Elite, despite its troubles, and slightly warmer than the Pure Base 600’s best effort of 55.6 degrees. For hot GPUs, like blower arrangements, a low front intake fan or replacing the drive cage with a bottom intake is a must.

Noise Levels


Although the “Define C - Window” has one fewer noise-damping panel than the non-windowed variety, noise levels remain competitively low. The Define C is a strong contender in our “quietest cases that don’t directly reference silence in the brand name” category, at 34.8 dBA with the top closed (as it generally should be) and fans at maximum RPM (which they generally won’t be). In fact, the only case which beats the Define C at a comparable fan speed is the Pure Base 600, which has specially designed fans that still rotate about 130 RPM slower.




This isn’t a flashy or exciting case, but it’s well-made and logical. The Define C makes it seem strange that there are cases that aren’t designed like it is: everything fits, everything works, it’s quiet, and it’s tiny. None of the features that make it so pleasant to work with (good cable routing, big chunky filters, well-fitting side panels) are complicated, and it’s easy to forget that the combination of all these features isn’t commonplace. The major downside is thermal performance, which is to be expected in a case with so little empty space. Large, hot GPUs aren’t a good fit for this case with the default fan arrangement, but fans can easily be added. We wouldn’t recommend higher wattage GPUs if desiring lower GPU fan RPMs, as the potential to limit thermal headroom on the clock is very real. For everything else, the Define C is well-priced for those who really want a small-footprint, and an objectively quiet case that can still fit a full-sized ATX board and some radiators.

Editorial, Testing: Patrick Lathan
Host, Test Lead: Steve Burke
Video: Andrew Coleman

Last modified on March 27, 2017 at 2:48 pm

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