Corsair Carbide 400C Review vs. S340, P400 - The Most Comprehensive Benchmark

By Published February 03, 2016 at 6:11 pm
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Teased at CES 2016, Corsair's 400C ($90) enclosure swiftly followed the chart-topping 600C, a case that dominated our GPU cooling charts. The 600C and 600Q cases instituted an inverted motherboard layout – rotating and flipping board installation such that the GPU is oriented “upside-down” – but stuck with tried-and-died optical drive support. To allow for an enclosure more fitting of the “mid-tower” form factor, Corsair removed the 5.25” support in its new Carbide Series 400C & 400Q cases, shrinking the height from ~21 inches to ~18.27 inches.

This review of the Corsair Carbide 400C benchmarks cooling performance for CPUs and GPUs, all accompanied by build quality and installation analysis. The 400Q is more-or-less the same case, just with the window removed and sound-damping material added.

Corsair 400C Gaming Case Specs

Case Carbide 400C Carbide 600C
Motherboard Support ATX ATX
Cooling Included:
Front: 1x140mm
Rear: 1x120mm

Front: Total 2x140mm / 3x120mm
Top: 2x120/140mm
Front: 2x140mm
Rear: 1x140mm
Note: 600Q only 1x140 Front

3x120/2x140 Bottom
Radiator Support Front: 360mm
Top: 240mm
Rear: 120mm
Front: 240/280mm
Rear: 140mm
Bottom: 280/360mm
Expansion & Bays 0x5.25”
7 expansion slots
8 expansion slots
Front I/O 2xUSB3.0
3-Speed Fan Controller
PSU Form Factor ATX ATX
Clearances CPU Heatsink: 170mm
PSU: 200mm
GPU: 370mm
CPU Heatsink: 200mm
PSU: 210mm
GPU: 370mm
Dimensions 425 x 215 x 464mm 454 x 260 x 535mm
Price $90 to $100 $150

Corsair 400C Layout Walkthrough

Corsair's 600C took risks. The case uses an inverted motherboard layout, something discussed extensively in our previous review, and reminds us of a select group of Cooling Elite in this regard. But it's those same risks which increase the case's cost – new tooling often has that effect – and push some users away. For that, Corsair's designed its more compact Carbide 400C.

But the 400C isn't totally without risk: It's ditching the 5.25” optical drive bays, something NZXT famously did with its H440 and carried on with the competing-class S340.

The 400C ditches its larger counterpart's inverted motherboard layout, instead reverting to familiar territory and exposing the board to the left side. Stock cooling is simplified to a set of two fans, one 140mm and one 120mm, shooting a straight line of air from the front-top and out the back-top. Because the 400C's PSU shroud has been shifted to the bottom, two top-mounted fans can be installed as optional add-ons or for large radiators. We tested a few non-stock configurations to determine which setup made the most sense when looking at CPU and GPU thermals; more on that below.


The motherboard tray is flanked by cooling and a power supply shroud. Corsair deploys a familiar design approach to the 600C's shroud, but the plastic cable concealer is functionally different. The 400C's shroud uses a two-piece, all-plastic system (sort of like the ancient HAF X). Pulled apart, there's better accessibility to removable, bottom-mounted drive cages and the PSU's cabling. A slot aligns between the separable shroud components, funneling direct-to-GPU wiring for cleaner cable management. This is something we complained about with the 600C, demanding a PCI-e hole be cut into the shroud, and is a noticeable improvement for clean cable management.

Externally, the case fronts Corsair's newest design choices, as introduced on the 600C. Flat, smooth paneling adorns the front, top, and right side of the case, exposing internals with a large side window (somewhat of a Corsair trademark, at this point). A fair mix of curves and hard edges comprise the case's exterior. As often stated in these reviews, we try to stay away from aesthetics for the most part – but it's worth some discussion. The decision to mix a curved top-front bezel with hardened edges elsewhere in the case, particularly the PSU shroud's jutting angularity, does feel a bit haphazard and lacking of cohesion in overall design. Small beans, really – the rest of the case is unoffensive and cleanly executed, which is about all we ask for in a case. Such is the nature of an objective, data-driven website. The photos and video b-roll should help you formulate opinions.

Corsair 400C Ease-of-Installation, Build Quality, & Cable Management


Installation is standard and without frills. Management room is ample, accessibility to oft hard-to-reach EPS 12V cables is made easy, and there's no fuss with core component clearances. The SSD sled has a clever mounting mechanism to make for easy extraction and addition of rear-of-tray SSDs, partly negating the issues we had with the front-side drive cages.

PSU mounting forgoes the externally-fitted bracket of the 600C, instead deferring to a standard set of four screws and rear-first installation. Despite support for 200mm PSUs, we had to remove the bottom hard drive cages to accommodate our 180mm test power supply. The PSU technically mounted, but cabling was hellish and pressed against the cages, making it effectively inaccessible and unsupported. We wish this would be made more clear in documentation, but PSUs nearing the 180mm form factors will likely force removal of bottom-mounted drive cages, lest cabling is kinked into uncomfortably angled/forced positions.

Another note on the PSU is its shroud: The 400C's PSU shroud forced us to route front I/O connectors above the PSU shroud (could not reasonably fit any other way – either due to length or the shroud's restrictive space). It's a bit uglier that way, but does work. Corsair should seriously consider lengthening front I/O cables or finding a better way to slot the front half of the PSU shroud into its rear structure. The PSU shroud runs so close to the FPC on the motherboard that cables can get pulled (undesirably), pinched, or completely forbid the locking action of the PSU shroud components. After fighting with it for a few minutes, we were able to assemble the shroud and route its neighboring cables with acceptable results – it's mostly aesthetic, after all – but life would have been much easier with the aforementioned changes.

Test Methodology

We tested using our Ivy Bridge test bench, detailed in the table below. This particular configuration has been retired and brought back into service, following some changes to our hardware availability. We’ve moved from a one-bench-fits-all setup (which uses a Haswell config in an mATX board) to multiple benches, one for mATX and small towers and one for ATX / mid-towers. This bench is for the latter.

Conducting thermal tests requires careful measurement of temperatures in the surrounding environment. We control for ambient – which is set to a constant 21C – and then produce charts using a Delta T(emperature) over Ambient value. This value subtracts 21C from the measured output, 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. 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 use a custom fan curve that was devised in-house after a series of testing; setting the CPU fan to its maximum speed can limit the disparity shown from case-to-case as the CPU cooler is extremely efficient, and will create a ceiling for thermal performance if bottlenecked.

  Component Courtesy Of Price
Video Card GTX 980 Reference
(PhysX) MSI GTX 980 Gaming
CPU Intel i5-3570K @ Stock GamersNexus -
Motherboard MSI Z77-GD65 GamersNexus -
Memory HyperX 2x4GB 1866MHz Fury Kingston $45
SSD HyperX Predator PCI-e 480GB Kingston $400
PSU Enermax Platimax 1350W Enermax $200
Case This is what we're testing! - -

Additional thermal testing was conducted for the Corsair 400C case – something we're continuing from the Manta – for determining the best possible fan configuration. The following matrix was engineered for positional testing of radiators and case fans in the 400C.

  Front Top BACK Top FRONT Rear Total Fan #
Stock 1x 140 intake 0 0 1x 120 exhaust 2
+1x 140 Front 2x 140 intake 0 0 1x 120 exhaust 3
+1x 140 Front
+1x 140 Top-Front [E]
2x 140 intake 0 1x 140 exhaust 1x 120 exhaust 4
+1x 140 Front
+1x 140 Top-Front [I]
2x 140 intake 0 1x 140 intake 1x 120 exhaust 4
+1x 140 Front
+1x 140 Top-Rear [E]
2x 140 intake 1x 140 exhaust 0 1x 120 exhaust 4
+1x 140 Front
+2x 140 Top [I]
2x 140 intake 1x 140 intake 1x 140 intake 1x 120 exhaust 5

Our objective was to figure out the optimal number and orientation of case fans in the Manta and now the 400C.

The video card is configured to run at 55% fan speed at all times. Stock clocks are used. We employ an NVIDIA GTX 980 reference for the case test bench.

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 twenty 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 “Titan Lake” stress testing simultaneously. Testing is completely automated using in-house scripting, and executes with perfect accuracy on every run.

Note: We retested the Corsair 600C following some configuration changes to our test environment. We've introduced additional measurement tools, so these results are not comparable to our previous benchmarks. The NZXT S340, Corsair 600C & 400C, Rosewill Gungnir, and Phanteks P400 were all freshly tested with our new instruments.

Continue to the next page for thermal benchmarking and optimal case fan placement.

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Last modified on February 08, 2016 at 6:11 pm
Steve Burke

Steve started GamersNexus back when it was just a cool name, and now it's grown into an expansive website with an overwhelming amount of features. He recalls his first difficult decision with GN's direction: "I didn't know whether or not I wanted 'Gamers' to have a possessive apostrophe -- I mean, grammatically it should, but I didn't like it in the name. It was ugly. I also had people who were typing apostrophes into the address bar - sigh. It made sense to just leave it as 'Gamers.'"

First world problems, Steve. First world problems.

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