Home Fractal Design’s Define C case reviewed

Fractal Design’s Define C case reviewed

Renee Johnson
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Something a little weird is happening in the world of DIY PCs of late. Look at Z170 motherboards—probably the most popular platform for enthusiast system builds these days—and you’ll see an abundance of ATX options alongside just a handful of microATX and mini-ITX boards. Awareness of those small-form-factor boards seems to be higher than it’s ever been, but we’re still a long way away from those form factors becoming default choices for the average system builder.

Even if motherboard makers are still putting the majority of their time and effort toward ATX boards, other developments around those PCBs are lessening the need for huge cases. CPUs and graphics cards are becoming surprisingly efficient, and that trend means hulking power supplies are no longer necessary in most builds. Copious gaming power can come from graphics cards under seven inches long. Storage devices are becoming denser, so one or two spinning disks can replace a hefty complement of 3.5″ drives. All of those changes make full towers and even large mid-towers seem ideal for only the most power- and storage-hungry builds.

In keeping with this new reality, the ATX mid-tower is shrinking. We’ve already seen what’s possible from a compact mid-tower with Corsair’s Carbide Series 400C, and Fractal Design is hopping on board that train today with the Define C. Despite its ATX motherboard tray, the Define C’s wheelbase is two inches shorter than even the microATX Corsair Obsidian 350D’s, and it’s only a hair taller than Corsair’s compact case. When one can have a space-saving ATX case like this one, it’s hard for me to imagine why many builders would want to bother with the limitations of microATX. Might explain the slim pickings for those boards on Newegg right now.

Thanks to its ATX bones, the Define C still offers full seven expansion slots and room for 168-mm-tall CPU coolers, 280-mm or 360-mm front radiators, and 240-mm top radiators. Despite its compact frame, Fractal’s latest can still swallow 12.4″-long graphics cards, too. The only things it can’t hold are tons of storage devices, optical drives, complex liquid-cooling loops, or super-long power supplies. Builders only get two 3.5″ combo sleds and three dedicated 2.5″ mounts for storage in the Define C, and that’s it. For modern system builds that tend to pair one capacious SSD with one hard drive, though, those specs seem just right.

Every time a Fractal case comes through the TR labs, it’s fun to see what new refinements have made their way in. The Define C is the first Fractal case I’ve used that includes a dust filter for the top ModuVent panel—a welcome development after years of badgering on my part. Fractal’s engineers have carried over the best features from the company’s other cases, too. The C gets the Define Nano S’s noise-dampened front panel, and it also gets the Define R5’s full-length bottom dust filter that pulls out from the front of the case. While the Define C’s left-side windowed panel isn’t dampened, the right-side panel keeps the same thin sheet of noise-dampening material common on other Fractal cases.

Up top, the Define C offers two USB 3.0 ports, a headphone jack, and a mic jack that flank the company’s signature big round power button. The C’s ModuVent is the same single-panel design that debuted on the Define Nano S instead of the three-panel covers on the Define S and Define R5. While this design is slightly less versatile than those on Fractal’s bigger cases, the included dust filter at least means that popping off the panel won’t allow dust to make its way in through unoccupied radiator or fan mounts.

The Define C rests on four rubber-padded feet. The full-length bottom dust filter seen here will prevent dust from making its way into the power supply or into the case through the optional 120-mm bottom fan mount.

Behind the padded front panel and a pop-out dust filter, Fractal includes one of its Dynamic X2 GP-12 120-mm fans. As many as two 140-mm or three 120-mm spinners can draw air in through the Define C’s front end, though triple-fan or 360-mm radiator setups will require builders to ditch the 3.5″ drive cage. We’ll examine why when we take apart the case shortly.

Around back, we get a glimpse of the Define C’s other included 120-mm fan, its seven white expansion slot covers, and the removable power supply mounting bracket.  Even though the C only has a 120-mm fan mount at its rear, Fractal kept the adjustable mounting system that we’ve praised in its past cases. That sliding fan could prove handy for builders with top-mounted radiators in mind.

Here are the Define C’s specs in convenient tabular form:

  Fractal Design Define C (with window)
Type ATX mid-tower
Dimensions (W x H x D) 8.3″ x 17.3″ x 15.7″  (210 x 440 x 399 mm)
Supported motherboards Mini-ITX, microATX, ATX
3.5″ drive mounts 2
2.5″ drive mounts 3
5.25″ drive bays None
Fan mounts 3 120-mm or 2 140-mm front fans
2 120-mm or 140-mm top fans
1 120-mm rear fan
1 120-mm bottom fan
Radiator mounts Front radiators up to 280 mm or 360 mm long
(with hard drive cage removed)

Top radiators up to 240 mm or 280 mm long
(motherboard heatsinks cannot exceed 40 mm tall)

One 120-mm rear radiator
(radiator cannot be more than 125 mm wide)

Included fans 1 Fractal Design Dynamic X2 GP-12 120-mm front fan
1 Fractal Design Dynamic X2 GP-12 120-mm rear fan
Front panel I/O 2x USB 3.0
Max. graphics card length 12.4″ (315 mm)
Max. CPU cooler height 6.6″ (168 mm)
Gap behind motherboard 0.75″ – 1.5″ (19 mm – 38 mm)

Fractal suggests a $79.99 price tag for the non-windowed Define C and a $84.99 sticker for the windowed version we’re reviewing today. Compared to other compact ATX cases, those price tags are quite aggressive—Corsair’s 400C goes for an even $100 for similar specifications. Let’s see what those dollars get you inside the Define C now.


Diving in
Getting inside the Define C is as simple as it gets—the side panels both use a swing-away latch instead of the increasingly primitive-feeling tab-and-slot mechanism common on many other cases. Taking off the panels reveals one new feature for a Fractal Design case that I’m not too hot on: a non-removable power-supply-and-storage cover. These shrouds are getting more and more common in today’s cases, and companies seem to have settled on two basic approaches: a removable plastic shroud or a riveted-in metal cover. I prefer removable shrouds for their convenience during the build process, but others might prefer the inherent rigidity of a permanent solution.

Since the Define C is so stubby, its main chamber makes no provisions for storage devices at all. That area is given over entirely to a deeply inset motherboard tray ringed by a set of rubber grommets. Sadly, the power supply cover has no dedicated holes in its surface for PCIe power connectors, as we get in the 400C or Cooler Master MasterBox 5. That decision does make for a cleaner-looking interior, but it might make cable routing a challenge down the line. The Define C does have a pair of large grommets at the forward edge of its motherboard tray, at least.

Flipping the Define C around reveals a bottom chamber design similar to the one we took issue with in Zalman’s Z9 Neo. From the power-supply mount to the edge of its 3.5″ drive cage, the Define C has 9″ of space on the dot. Standard ATX power supplies measure about 5.9″ long, so there’s only about 3″ of space available in front of the PSU for cable storage. Folks looking to add or remove cables from their modular PSUs will probably need to slide the unit out of the case using the thumbscrew-secured mounting bracket to make room for their hands.

The Define C also has only three-quarters of an inch or so of cable-routing space behind its motherboard tray at its tightest point. Fractal Design seems to be nudging builders toward routing as many of their cables as possible through the roughly 1.5″-deep channel at the front of the case. Considering that power and data cables for the SSD mount and the four- or eight-pin EPS connector have to go directly behind the motherboard regardless, we’d have liked to see a slightly roomier area back there.

For builds that do without 3.5″ storage devices entirely, the dual-drive 3.5″ cage can be removed with a quartet of screws underneath the case. Once the drive tray is out, builders also have the option to remove a metal cover that sits above the cage for extra radiator or cable-routing space using a pair of screws behind the front panel. Fractal’s attention to detail shows with this cover: even though most people will never see its underside, all of its edges are nicely rounded offand it fits into its cut-out without the slightest gap.

Personal preferences about removable power-supply covers aside, the Define C’s interior largely appears to uphold Fractal’s reputation for well-designed, easy-to-use cases. Let’s see if those impressions hold up in practice.

The build

If you’ve read any of our other reviews of Fractal Design mid-towers, you already know what’s coming in this section. Getting our motherboard, CPU cooler, and graphics card into the Define C’s main chamber was an effortless process. We didn’t run into a single hitch, and our finished build looks quite slick thanks to the power-supply shroud and cable grommets ringing the motherboard tray.

Running cables to each of those components proved a little tricky, though. Since the Define C has so little space in front of its power supply, we had to carefully stuff any unused cable lengths into that tiny gap. The hook-and-loop straps in the C’s main cable-routing channel helped keep most of the potential cable-routing disorder in check, though. While we did find enough space to stow cables in the end, I feel like it would have been nice to have another half-inch or so of room behind the Define C’s motherboard tray. As it stands, this relatively cramped area is the only minor blemish on an otherwise smooth build.


Our testing methods
Here are the specifications of our test system:

Processor Intel Core i5-6600K
Motherboard ASRock Z170 Extreme7+
Memory 16GB (2x8GB) G.Skill Trident Z DDR4-3000
Graphics card Asus Strix Radeon R9 Fury
Storage Two Kingston HyperX 480GB SSDs
WD Black 1TB 7200 RPM hard drive
Power supply Seasonic SS-660XP2
CPU cooler Cooler Master MasterAir Pro 4
OS Windows 10 Pro

Our thanks to ASRock, G.Skill, Asus, Kingston, Western Digital, and Cooler Master for contributing parts to our test rig, and to Fractal Design for providing the Define C for review.

Our case-testing cycle consists of the following phases:

  • 10 minutes idling at the Windows 10 desktop
  • 10 minutes running the Prime95 Small FFTs CPU torture test
  • 10 minutes running Prime95 and the Unigine Heaven GPU benchmark
  • 10 minutes idling at the Windows desktop

We use the following software in our case tests:

  • Prime95 version 28.10
  • AIDA64 Engineer 5.80.4000
  • Unigine Heaven 4.0

Cooling performance
Here are the results of our cooling tests, plotted over time:

And here are the minimum and maximum temperatures of our test system’s components during each testing stage:

You’ll have to excuse us for a couple weird results in these tests—it seems an application was loading our graphics card in the Define C during its idle phase, and AIDA64 didn’t gather hard-drive temperatures in the Define S. Even so, we think we have a pretty good picture of the cooling performance of these cases.

Despite the Define C’s compact size and smaller fans, it’s no less effective at cooling the system inside compared to the larger Define S and its 140-mm spinners. Both cases keep our test system’s components within a couple degrees Celsius of each other, and none of the numbers suggest reason for worry.

Noise levels
Here are the noise levels we measured during the idle and load phases of our tests. Each measurement was made 18″ from the top, left, right, and front of the cases being tested using the Faber Acoustical SoundMeter app running on an iPhone 6S Plus.

At idle, the Define C and Define S are both flirting with the noise floor of our testing environment. The only audible noise from either case is the sound of the hard drive motor in our WD Black 1TB drive. The Define S does emit more noise from its right side than the Define C does, however, possibly thanks to the close proximity of its hard-drive mounts to the right side panel. Under load, these Defines deliver practically identical sound pressure levels at every measurement point. That performance is in keeping with the Define C’s thermal figures: it’s not working any harder than the larger Define S to keep the components inside cool.

From a subjective standpoint, the Define C’s included fans are just as good as the 140-mm fans in the Define S and Define R5. They’re inaudible at any reasonable distance while the system inside idling, and they only add the slightest whooshiness to the case’s noise character under load. That whooshiness is eclipsed by the sound of the graphics cooler on our Asus Strix R9 Fury card, so it’s not a concern for folks trying to minimize component noise.

Honestly, if minimizing component noise is a priority, the best thing one can do for either of these cases is to ditch the hard drive. I measured a 28.5-dBA idle SPL from the left side of the Define C with the hard drive off—a major improvement considering how quiet these cases are to begin with. With the 3.5″ mechanical drive out of the picture, these cases deliver near-silent computing.


After my time with Fractal Design’s Define C, I find myself marveling at just how huge and ungainly most of the other ATX mid-towers in my house now seem. If one can fit an ATX mobo, an enormous and power-hungry graphics card, and all the trimmings into a case that’s no bigger than the average microATX tower, I see no reason not to go with the best of both worlds from here on out.

One part of the C’s design suggests a future imperfect. Its permanent power-supply shroud makes clean-looking builds easy, but it also poses some cable-routing and cable-storage challenges. A modular power supply is all but required for this case, and plugging extra cables into such a unit will require builders to slide out the PSU any time an adjustment is required. Once all those cables are in place, owners might also have to perform a bit of cramming and squashing to tame the cable nest underneath the shroud. These are all minor issues, to be fair, but I’ve never used a Fractal mid-tower that I’d call “cramped” in any way before my experience with the Define C.

Those minor quibbles aside, the Define C turned in great performance once we wrapped up our build. Fractal Design’s included fans kept our Casewarmer testing system cool and quiet under load, and a bit of hard-drive noise was the only indication our system was on at all while it idled in this case. Cut 3.5″ storage out of your build entirely—an increasingly attainable dream these days—and this case will treat you to near-silent operation at idle.

Fractal Design Define C
November 2016

All told, Fractal’s latest delivers every bit of the clean styling, quiet manners, modular touches, and solid performance we’ve come to expect from the company’s other cases. For systems with one hard drive, one SSD, and one graphics card—that is to say, every Skylake-powered build in our System Guide—the Define C seems like a perfect fit. Space-conscious builders who still value expandability can rest easy with this microATX-sized ATX mid-tower, as well. That long list of virtues comes with a competitive price tag: $80 for the non-windowed Define C, or $85 for the fenestrated version we tested.

Unless you absolutely need the Define S’s custom-liquid-cooling-friendly insides or the Define R5’s copious 3.5″ bays, the Define C seems like the way to go in Fractal’s lineup for the average new system build. If this case represents the future of the ATX mid-tower, we think it’s a bright one—and it’s made all the brighter for Fractal Design by another gleaming TR Editor’s Choice award.

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