When Fractal Design introduced its Define S chassis a little over three years ago, PCs—and indeed, PC cases—looked a lot different than they do now. Power-supply shrouds were rare, and builders didn’t take any issue with a neat bundle of slack cabling zip-tied up in front of their PSUs. Since that time, most every case designer has embraced the shroud at every price point. A visible power supply and cabling these days is kind of like jorts: functional, but unfashionable.
The space demands on the average case have changed, too. With the ever-greater density of hard drives and the increasing accessibility of NAS boxes, builders don’t need 10 local 3.5″ devices to reach 10 TB of storage in a system. They can just slap one big drive in there or plug in a Gigabit Ethernet cable to reach their disk array. SSDs don’t take up as much space as they used to, either. Builders rarely need to choose 2.5″ storage when even SATA SSDs can go right on the motherboard, and the majority of NVMe drives need an M.2 slot to work at all.
Some elements of a system build aren’t so amenable to miniaturization, of course. Radiators can’t escape the laws of thermodynamics, for just one example, so lots of heat still means lots of surface area for those after quiet cooling. Reservoirs usually put a big cylinder or two of liquid on top of their accompanying pumps, too. All that stuff needs space, and the wide-open design philosophy of the original Define S remains valuable for the kinds of builds that just can’t go in cases with less-spacious main chambers.
To keep up with the changing demands of case design, Fractal Design has evolved the Define S into something a little different. No longer is this case a budget-friendly alternative to the Define R6. Instead, the Define S2 we’re reviewing today takes the premium-feeling skeleton and user-friendly design features of the R6 and wraps them around the same wide-open interior as the original—just with a PSU shroud to hide the naughty bits.
Let’s start from the top. A single, full-length metal ModuVent panel crowns the Define S2, a design that debuted on the Define R6. A button at the left rear corner of the case pushes forward a row of catches that pop up the panel, allowing it to be pulled away from the rest of the case.
With this panel off, we get a good look at the Define S2’s removable top radiator mount. Unlike other cases that implement this feature, the Define S2 (and R6) ask the builder to remove a few tiny screws from all over this panel to pull it out, rather than simply slide it out from the inside of the case. This design works fine in practice—just keep track of those screws.
The Define S2’s top mount can handle as many as three 120-mm or 140-mm fans, or 360-mm or 420-mm radiators for the liquid-cooling set. Using any 140-mm-based radiator on the top panel requires motherboard components not to exceed 1.38″ (35 mm) in height, however. At least in the case of 120-mm-based radiators, the top mounting frame has a generous offset from the motherboard tray to prevent interference with tall DIMMs or motherboard heatsinks.
Observant readers will be asking themselves how the top radiator mount is supposed to breathe if the top panel of this case is a solid affair. Surprise: there’s a captive mesh filter hiding underneath it.
Of all the changes Fractal Design made in moving from the Define R5 to the Define R6, this one is my least favorite. I found it impossible to pull the panel and cover apart while working with both cases without using some kind of flat-edged tool, and in the case of the Define S2, I still barked my fingers on the edges of this metal panel while I was working to separate them. I haven’t bled from working with a case this expensive in a long time, and I don’t think it speaks well to Fractal Design’s efforts here.
The front I/O panel of the Define S2 includes the company’s signature circular power button, a reset button, two USB 2.0 ports, two USB 3.0 ports, the usual headphone and microphone jacks, and a bona fide USB 3.1 Gen 2 Type-C port. The cable for this Type-C port can handle data transfers at speeds up to 10 Gb/s, as well as fast charging for motherboards and devices that support it.
Since the Define S2 doesn’t have an optical drive, the front panel doesn’t have the reversible door of the Define R6. It’s just a pop-off panel, albeit one covered in a real sheet of black anodized aluminum for a classy appearance.
Behind this panel, Fractal hides one of its trademark sheets of noise-deadening foam. This material is meant to diminish any din from inside the case that might escape through the rows of vents running up the sides of the panel.
While you won’t find a full-length dust filter attached to the Define S2’s front panel as you would in the original Define S, Fractal still filters the case’s intake by way of a pair of snap-in mesh covers that run behind the panel’s louvers.
Flipping the case over reveals another Fractal trademark: a full-length dust filter that pulls out from the front of the case. Underneath this filter, the Define S2 has a pair of 120-mm or 140-mm fan mounts that can either pull air in or push it out of the bottom chamber, PSU length permitting.
Those same mounts can handle radiators as long as 240 mm or 280 mm, as well, though again, the PSU’s length will be the limiting factor.
Around back, the Define S2 shows the first real evidence of its non-removable PSU shroud with a thumbscrew-retained PSU-mounting frame. We also get a look at its seven expansion-card slots, its vertical graphics-card mount (made useful by the optional Flex VRC-25 cable, sold separately) and the dual-purpose, adjustable 120-mm or 140-mm fan mount. Fractal pre-populates this mount with another one of its Dynamic X2 GP-14 140-mm fans. Radiators that fit 120-mm or 140-mm mounts can go here, too. Finally, we can see the aforementioned button that pops out the top panel.
|Fractal Design Define S2|
|Dimensions (W x H x D)||9.6″ x 23″ x 22.7″
(24.3 cm x 58.6 cm x 57.7 cm)
|Supported motherboards||E-ATX, ATX, microATX, Mini-ITX|
|3.5″ drive mounts||3|
|2.5″ drive mounts||7 (3 shared with 3.5″ devices)|
|5.25″ drive bays||N/A|
|Fan mounts||Front: 3x 140 mm, 3x 120 mm
Top: 3x 140 mm, 3x 120 mm
Bottom: 2x 140 mm or 120 mm
Rear: 1x 120-mm or 140-mm
|Radiator mounts||Front: 120-mm rads up to 360 mm, 140-mm rads up to 280 mm
Top: 120-mm rads up to 360 mm, 140-mm up to 420 mm
(mobo and DIMM clearance of 35 mm max with 140-mm top rads)
Rear: 1x 120-mm or 1x 140-mm rad
|Included fans||Front: 2x Fractal Design Dynamic X2 GP-14 140-mm fans
Rear: 1x Fractal Design Dynamic X2 GP-14 140-mm fan
|Front panel I/O||2x USB 3.0, 2x USB 2.0, 1x USB 3.1 Gen 2 Type-C,
headphone jack, microphone jack
|Max graphics card length||17.3″ (44 cm) with fans installed, 18.3″ (46.5 cm) without|
|Max CPU cooler height||7.28″ (18.5 cm)|
The Define S2 will come in four colors, all with tempered-glass side panels. One is the black-and-white-trimmed version we have on the bench today. The second is a “Blackout” version that drops the contrasting white expansion-slot covers and fan hubs. The third is a “Gunmetal” model with a smoky-gray anodized-aluminum panel and paint job, plus black fans and a slightly tinted tempered-glass side panel. The final variant is a white version with white fans, a white-bordered tempered-glass panel, black expansion-slot covers, and a black aluminum front panel. The basic black and white models will come with blue power LEDs, while the Blackout and Gunmetal finishes will have white power LEDs.
No matter what Define S2 model you choose, the case carries a $149.99 suggested price tag. For a case that’s resolutely free of RGB LEDs or other gimmicks, that sticker is going to make builders place a premium on construction and ease of use. Let’s pop open the Define S2 now and see what’s going on inside.
Although Fractal Design secures the Define S2’s side panels with thumb screws, they’re totally optional once the case has reached its final destination. The actual job of holding in the side panels falls to a ball-and-socket mounting system that’s both easy to use and avoids the visible screws that hold other cases’ tempered-glass side panels in place.
Looking into the main chamber, we can see a lot of the same features that defined the Define S. Namely, there are no obstructions anywhere inside save for the non-removable PSU shroud at the bottom of the case. The top of that shroud is ventilated to allow graphics cards in multi-GPU setups to breathe through the air space in the bottom chamber. To permit long radiator-and-fan stacks or pumps to be installed in the front of the case, a removable cover needs to come out. Otherwise, that cover keeps the PSU shroud looking clean.
A “pegboard” area sits ahead of the rubber-grommet-ringed motherboard tray, where builders can secure practically any hardware they can improvise brackets for. Fractal Design includes a pair of reservoir brackets that can secure fluid-filled cylinders to this area, though builders are on their own past that.
The Define S2’s motherboard tray can accommodate motherboards as large as ATX or E-ATX form factors, although using big-daddy boards will block the cable-routing grommets in front of the tray. The resulting limitations on cable-routing options should give builders using that rare form factor pause. A large grommet atop the PSU shroud might offer a way around that issue in a pinch. Builders can put a pair of 2.5″ devices atop the PSU shroud to show them off, too.
Behind the motherboard tray, Fractal provides 0.9″ (23 mm) of cable-routing space, an adequate but not exactly roomy figure. Builders who want to conceal their 2.5″ storage from view entirely can do so with two dedicated 2.5″ storage trays, while three 3.5″ trays behind the “pegboard” provide room for 2.5″ or 3.5″ devices alike.
To lessen the cable-routing challenges of wide, flat SATA power cables behind motherboard trays, Fractal includes its own proprietary SATA power extension cable that uses tight wire bundles for clean routing. This extension plugs into the end of any SATA power cable, although that cable will then need to be stuffed into the space ahead of the PSU.
Because of the behind-the-pegboard 3.5″ cages, however, the entirety of the power-supply chamber is available for cable-storage purposes, unlike cases that cram their more permanent 3.5″ mounting setups ahead of the PSU and create seriously cramped cable-storage spaces under shrouds. In keeping with the SATA power cable, Fractal also sleeves the usually-meddlesome front-panel connector wires for a clean look in the final build.
The final point of note behind the motherboard tray is the case’s built-in fan hub. This hub can provide power and PWM signals to up to three fans, and it can also drive up to four more three-pin fans.
Even with a massive 360-mm radiator installed, the Define S2’s main chamber still has plenty of space ahead of its motherboard tray. To really fill up this chassis, one would need to bring a custom loop and its attendant reservoirs and pumps into the picture.
While I was positioning the massive radiator of our closed-loop liquid cooling system, I really came to appreciate the Define S2’s removable top radiator mount. I had to test-fit that heat exchanger several times to get its cabling in the right place, and being able to pop out the top mount kept me from throwing tools as I arrived at a cable-routing path that worked. At least with our 360-mm rad, the case’s offset radiator mount offered us plenty of room to work with our tall DIMMs and motherboard heatsinks, too—not at all a given with less thoughtfully designed cases. Builders using 280-mm or 420-mm rads won’t be so fortunate, however, as I noted in my intro.
Looking at our final cable-routing scheme, it’s clear that some cables in the Define S2 could stand to be a bit longer. The USB 3.1 Gen 2 connector had to run between the first and second hard-drive cages to leave me enough length to hook it up, and the same held true of the cables from the front fans. While the high-speed USB 3.1 Gen 2 connection might not work over a longer cable, I don’t think there’s much cause for the fan cables from the front panel to be as short as they are on this case. Either way, the resulting cable-routing scheme could make for trouble in a system with more 3.5″ devices.
Getting the bulky USB 3.0 connector around the bottom 3.5″ cage and out to our motherboard ultimately worked, but as with the fan and USB 3.1 Gen 2 cables, the USB 3.0 cable had only just enough slack to make its connection. Given how little strain relief that bulky connector has, hooking it up without much slack isn’t the greatest feeling.
While I was running cables, I found that the fan hub of the S2 isn’t in the most convenient place. The EPS connectors from our PSU wanted to run right over top of the hub, catching unoccupied fan headers and even bending pins on the controller. A strategic zip tie would fix this issue in a more permanent build, but I still think the fan hub could stand to be moved out of the way of the most natural cable-routing path in this case somehow.
Cable-routing annoyances aside, the relatively wide frame of the top dust filter didn’t play well with the mounting screws for our radiator. Even a few millimeters of screw and washer protruding above the top radiator mount was enough to keep the filter from snapping back into place with ease. While I was able to sort of force the filter back into place and ultimately lock it onto its catches, the screws underneath forced it upward and led to some unsightly bulges along its length. Fractal Design’s engineers probably ought to consider molding some screw reliefs into the frame of this filter in future versions.
Despite the unobstructed space in front of the Define S2’s power-supply mount, I quickly discovered that the non-removable pegboard makes it tough to get one’s hand into that space and fish out any cables that one might need during the initial build process. Knowing what I do now, I’d fish out every cable I needed after threading the bundle through the Define S2’s PSU cutout and before sliding the power supply home. Anyone looking to add cables to their PSU in the Define S2 will probably want to back the PSU out of the case on its removable frame or pop open the cover on the forward half of the shroud for easier access.
Overall, the experience of building in the Define S2 was pleasant enough, but even Fractal Design’s best minds can’t get around the fact that a big metal cover on top of the power supply can make putting a build together harder than a case with a shroudless main chamber. I find it hard to fall in love with fiddly cases, and the Define S2 is a tad more fiddly than I’d like. Unforced errors like too-short cables are hard to forgive in a premium case, too. While I can understand the desire not to end up with a mass of unused wire from every connection, the Define S2’s fan and USB cabling didn’t give me as much cable-routing freedom as I’d like.
This is normally where we’d discuss cooling performance and noise levels, but I’ve got to apologize—I’m traveling as this review goes live, and I simply ran out of time to run those tests before I had to hit the road. Having built a high-end system in the Define R6 earlier this year, though, I know that the fundamental design Fractal is using here is more than up to the job of delivering effective cooling performance with little noise.
From the brief time I was able to spend with a system inside the Define S2, I have no doubt that the more open case is as proficient at staying cool and quiet as its relative. I’ll run those tests to be certain when I’m back in the TR labs, but I have no doubt the S2 will get my stamp of approval on both fronts.
Fractal Design’s Define S2 inherits a lot of the Define R6’s design decisions, and as I learned when I put together our Threadripper video-editing build in the R6 earlier this year, not all of those changes are steps forward from the Define R5.
The top ModuVent panel is now a full-length metal shell with a captive dust filter that can be installed on its own to open up the top fan and radiator mounts. I think it’s too clever a design by half. It’s way too hard—potentially injuriously hard—to separate the filter from the cover by hand, and frustrating to pull the two apart even with the assistance of a tool. The system is much, much more annoying to use than the trio of ModuVents on the Define R5 and Define S, even if it looks cleaner at rest.
Other changes to the Define S2 make for an easier building experience than in past Fractal Design cases. The removable full-length radiator mount at the top of the case needs some unscrewing to pull free, but once it’s out, that mount is convenient for wrestling extra-long radiators into place. The case’s thumbscrew-free side panels look cleaner than the average tempered-glass window, and they pop away with only a gentle tug despite feeling totally secure when they are locked in place. Fractal Design trademarks like foam-backed front and side panels might not be as unique as they once were, but they’re still as welcome as ever in the Define S2.
Fractal also sprinkles thoughtful touches throughout the case and its accessory box, like the included SATA power extension cable for clean wiring around its hard drive cages and sleeved front-panel wiring for a neat appearance when connecting those cables to the motherboard. A fan hub behind the motherboard tray can help minimize visible wiring for pumps or air movers, and Fractal’s behind-the-pegboard 3.5″ mounting system leaves the entire under-PSU-shroud open for cable storage or other creative uses.
If you’re not planning on installing a ton of 3.5″ drives and don’t need a 5.25″ bay, but you do plan to install lengthy radiators in your system, I think the Define S2 is actually a better buy than the Define R6 just because it’s simpler and cleaner-looking inside. To get our high-end Threadripper system into the Define R6, we had to discard its 5.25″ bay and collapse its 3.5″ drive-sled mounting points into the motherboard tray, something the Define S2’s pegboard does to begin with and in a more rigid way. The S2 also comes with a cover for its front-radiator cutout, while our Define R6 build ended up with a big hole behind the front fan mounts thanks to its lack of such a cover when its 3.5″ drive panel is collapsed.
Despite the precedent set by its predecessor, the S2 is no longer an under-$100 value option in the Define series. That segment of the market is now adeptly handled by the compact Define C series, so the Define R6 and Define S2 are now more special-purpose selections than a default choice. At $150 for its various configurations, DIYers need to be dreaming big to consider a Define S2, and our system build inside this case proves as much.
If you want a big case that’s easy to build big, powerful PCs in without much fuss, though, the Define S2 seems more than ready to keep those systems cool and quiet in operation. I think Fractal Design has made all the necessary pivots to keep the Define S concept relevant in this day and age.
I’ve yet to finish my performance testing of this case thanks to travel, but having built and worked with a high-end system in the Define R6 earlier this year, I’m confident that the Define S2 is every bit that case’s equal on the noise and cooling-performance front. I’m going to go out on a limb for the moment and provisionally call the Define S2 TR Recommended, but I highly doubt I’ll need to adjust that verdict when I run our cooling and noise tests.