NZXT S340 Case Review

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NZXT has put out a lot of shapely cases in past years. We’ve become accustomed to swoops and curves, glistening gewgaws, and fancy colors. But what happens when NZXT produces a flat black rectangle and calls it a computer case? Oh, sure. They sent me one with a window on the side, but still. Why would you want such an unprepossessing black box? Why indeed! Let’s explore and find out.


NZXT has been making cases since 2004. They’ve branched out a bit since then (well, more than a bit), but their roots go back to case-making. Unlike some manufacturers, the NZXT designers are based on the west coast of the US. The S340 is part of the Source series of cases. It comes in black, white, black-and-blue, and black-and-red.

Features (from NZXT’s product page)

  • 360° of steel casing surrounding the all-steel chassis
  • Grommet-less cable management bar keeps cables tidy with ease
  • Full 280 mm radiator support for the latest Kraken cooler
  • Compact form factor coming in two inches below competing mid towers
  • Detailed design and engineering with tons of small touches
  • Very easy to build in for new and experienced users alike
  • Integrated PSU shroud for an ultra clean build
  • Fully filtered intakes

Specifications (mostly from NZXT’s product page)

Model Number

CA-S340W-W1 (White)

CA-S340W-B1 (Black)

CA-S340MB-GR (Black/Red)

CA-S340MB-GB (Black/Blue)

Drive Bays

External 5.25″: 0

Internal 3.5″: 2+1

Internal 2.5″: 2+1

Cooling System

Front fans (optional): 2x 140mm/2x120mm

Top: 1x 140mm/120mm (1 x 120mm FN V2 Fan Included)

Rear: 1x 120mm (1 x 120mm FN V2 Fan Included)


Front (Included)

Bottom Rear(Included)

Radiator Support

Front 2 x 140mm or 2 x 120mm

Rear 1 x 120mm


GPU Clearance With Radiator: 334mm

GPU Clearance Without Radiator: 364mm

CPU Cooler: 161mm

Cable Management – Lowest Point: 17mm

Highest Point: 168mm

Stated Dimensions

(Measured Dimensions)

200mm x 445mm x 432mm

(7-7/8”W x 18-3/4”H x 17-1/2”D)


SECC Steel, ABS Plastic

Motherboard Support

Mini-ITX, MicroATX, ATX

Expansion Slots


External Electronics (IO)

1 x Audio/Mic

2x USB 3.0

Product Weight

7.05 kg


5060301691562 (White)

5060301691579 (Black)

5060301692644 (Black/Red)

5060301692637 (Black/Blue)


2 Years


815671012111 (White)

815671012128 (Black)

815671012371 (Black/Red)

815671012364 (Black/Blue)

Pay attention, campers. There is no place for a 5.25” optical disk drive. That’s not the important item to notice, though. NZXT has put the rear cable clearance up for you to see. Even better, they have put the CPU clearance there. Actually, that measurement is a tad conservative: the tallest tips of the NH-D14’s heatpipes did not scratch the acrylic window of the case side. As a rule of thumb, any case like this one that sports a 120 mm exhaust fan will accommodate a full tower heatsink. As for the dimensions, I measured this case. The depth includes the screws in the back.


The S340 came in a single box. As you can see, it got scuffed and bumped a bit. It was black on one side and white on the other.



When we dump the case from the box, we find a standard pair of Styrofoam end caps, and under those, a traditional plastic bag. Inside the bag, the case is clean. The plastic sheets that cloak the acrylic window cover it inside and out, doing a nice job of protecting said window.

Styrfoam End Caps
Styrfoam End Caps

Covered Windows
Covered Windows

The NZXT S340 – An External Tour

With all the plastic stripped off, the S340 stands as an edifice of blackness. Does this remind you of an old SF movie?

The left side of the S340 shows that the acrylic window is handsome as can be. We can see the grommet-less cable management bar showing its redness through the window. Aside from some thumbscrew heads sticking out the back end, there is little else to see. Let’s move on.

S340 Oblique
S340 Oblique

S340 Side View
S340 Side View

Next, let’s peer over the top. There we see a fan hole. The S340 comes with a perfectly serviceable 120 mm fan in that spot, but if you want to improve on it there is room for a 140 mm fan. Down from the fan we see the IO cluster, huddling to the right side at the front of the case. There are two USB3 ports there. At the very front of the case we spy the opening of a red tunnel, invisible from the front and sides. Clever little splash of color, that.

On the right side, we see – nothing. That’s right, it’s a flat black wall. Other than the heads of the thumbscrews at the back of the case and the sturdy feet underneath, there’s nothing to see here. Let’s move along.

The back of the S340 shows a 120 mm fan, seven slots – note that you can see its thumbscrews from outside the case – and the PSU hole, flanked by thumbscrews of its own. The one aspect of this that is interesting is how airy it all is.

Top View
Top View

Right Side
Right Side

Back View
Back View

Now, let’s look at the bottom of this case. There’s the red tunnel at the front that matches the one we saw at the top. That must be the front plate. Further up, we can see a restrictive grill covering where we expect the power supply to be. Also note the four wide feet, designed to hold up heavy contents, never to mar your table top.

Pulling off the restrictive grill, we see that it was covering slots that open to the PSU space.

Bottom View
Bottom View

Restrictive Grill Removed
Restrictive Grill Removed

Returning to the back of the case, we discover that the four thumbscrews are captive thumbscrews on a frame that holds your PSU, and allows it to slide into the back of the case. On top of that we have laid the restrictive grill that we go from the underside. The position of the restrictive grill means that it is nominally a dust filter. Well, it certainly is an inexpensive mesh, but dust filter it is not. Since it is so restrictive, it looks like the best thing you can do with it is to throw it away. Seriously, it is that bad. But don’t let this cheap substitute for a legitimate dust filter distract you from looking hard at this case. There is a lot more to look at.

Next, we will peer down the front tunnel. Where other cases use side vents to feed the front fans, the S340 feeds them from this top and the bottom vents. Clever. The noise of those fans is directed up and down, away from you. Good Move, NZXT. While we are looking, check out the IO cluster.

Restrictive Grill On PSU Bracket
Restrictive Grill On PSU Bracket

Top View of IO Cluster and Air Tunnel
IO Cluster and Air Tunnel

Popping off the front plate, which is a one-piece plastic unit, we see a full height dust filter. That filter is held on with magnets at the top, and a lip at the bottom.

Pulling it away, we can see that this is a first-quality dust filter. This is good as the bottom filter was bad. Behind the filer is – nothing. NZXT had the good sense to leave the fan openings free from obstructions. No “grill” there, just a high-quality dust filter. The hard drive enclosure is fairly obstructive, but that doesn’t matter because there is no fan the to provide airflow. So the front of the case behind the front cover is nice and open.

Front Plate Off
Front Plate Off

Magnet-Attached Filter Off
Magnet-Attached Filter Off

Touring Inside the S340

First let’s look at NZXT’s thumbscrews. Threaded toward the end, with the middle left bare of threads. This is a thumbscrew from the covers. It leaves the covers with captive thumbscrews.

Here we have the S340 with the left cover off. The bottom shows us that the space from the PSU to the hard drives will be enclosed by a tunnel. That means the PSU and the cables from it will be hidden. Items that stand out: the motherboard standoffs are pre-installed, there is a large angular CPU window and the cables running to and from the motherboard will normally be hidden by the “cable management bar.”

Captive Thumbscrew
Captive Thumbscrew

Inside the S340
Inside the S340

Looking inside the motherboard chamber, we can see both of the fans that come with this case. We can also see the seven PCIe slot covers, as well as the thumbscrews which secure them.

Looking up at the back of the case, we can see the power cable running from the fan at the bottom, up through a clip to the top and out of the chamber. This fan clip may be unique to the S340.

Exhaust Fan
Exhaust Fan

Fan Cable Clip
Fan Cable Clip

The center standoff is a thread-less “king post” you can use to stabilize your motherboard before you start attaching screws. This is always a welcome feature to see.

Next is a top view of that tunnel (NZXT calls it the “PSU shroud”). Here you can see the vents that allow the hard drive to cool passively. The picture also shows sleds for two 2.5” drives, presumably your SSD’s.

Threadless Kingpost
Threadless Kingpost

Vented Top of HD Enclosure
Vented Top of HD’s + 2 SSD Sleds

Getting to those SSD sleds, we see that they slide onto the top of the tunnel. The sleds are then affixed by thumbscrews. If you don’t want to screw your SSD’s down, the sleds grip them fairly firmly, so tool-free installation is possible here.

The next picture shows an SSD on one of the sleds. Instead of the NZXT manual, we have a hard drive visible through the slots. If you look off to the left, you will see the back frame partly out of the case, attached to its PSU. The cable pass-through holes continue our non-grommet theme here.

Details of SSD Sled
Details of SSD Sled

SSD in Place
SSD in Place

On the right side of the case, we can see behind the motherboard tray. The PSU-HD tunnel is accessible on this side. The “cable management bar” looks like it should be removable. The motherboard cables ends are covered with a bag and there are several tie-down points.

True to its specifications, there is 17 mm cable space behind the motherboard tray.

Behind the Motherboard Tray
Behind the Motherboard Tray

17 mm Space
17 mm Space

Looking down the tunnel from the back of the case, you can see the right wall of the HD enclosure. The holes there will allow you to fasten the right side of your hard drives to the enclosure. If you leave one side unfastened, the drive may rattle in your case. To fasten the screws, I advise you to get an 8” shank Phillips screwdriver, as you can see that the tunnel may cramp your style if you have fat hands. I needed my long screwdriver for this.

Here is the HD enclosure from its front. You can see that it is equipped with fingers to hold your drives. They’re not strong fingers. Remember the picture of the front of this case? Good. You can fasten the left HD screws from the front of the case. You can put two drives in the enclosure. To mount a third drive, you must fit it under the other drives and fasten it with screws to the bottom of your case. It’s not hard, but it is a bit tedious.

PSU-to-HD Tunnel
PSU-to-HD Tunnel

HD Enclosure
HD Enclosure

Looking up from outside the case behind the motherboard tray, you can see the place where your EPS-12V plug will go. That’s a pretty big opening, so you won’t have to struggle to get your CPU plug through.

Here are your accessories. Other than the cable ties, all of them come in appropriately labeled little bags. That bit next to the spare standoff is a standoff wrench. In addition to its ability to act like a thumbscrew on the sides, it has a Phillips socket on the top for using it with a screwdriver.

Space for CPU Plug
Space for the CPU Plug (EPS12V)


Building a system with the S340

NZXT wants you to think about this case when you use AIO’s. Here is an 240 mm AIO mounted to the front of the case. The next picture shows the NZXT Kraken fastened where NZXT wants you to put it, on the exhaust port of the case. Actually, I think it would work better up front, where it can breathe freely. But I suppose if you were thinking of doing that you would buy a 240 mm AIO.

Note that I had to remove the cable management bar to fit the 240 mm AiO into the case.

S340 with 240 mm AIO
S340 with 240 mm AIO

S340 with 120 mm AIO
S340 with 120 mm AIO

I tried to get the EK Predator 240 AIO into this case. It wouldn’t fit. The first picture shows what happens when you put the hose end uppermost. The bottom end of the IO cluster interferes with the AIO and the Predator 240 won’t fit.

The second picture shows what happens when you flip the AIO to put the hoses on the bottom. The unit is just a smidgen too tall to fit. If you were willing to mod your case a little bit and lengthen those screw slots, you could probably make it fit – if the IO cluster doesn’t stop the fit. But as-is, the EK AIO doesn’t fit.

EK Predator 240 mm Does Not Fit
EK Predator 240 mm Does Not Fit

Same Model Still Does Not Fit
Same Model Still Does Not Fit

Here is the NZXT S340 prepped for its testing. The two stock fans are in their stock places and connected there are three hard drives present, two connected. The SSD is connected. The heatsink, an NH-D14, is without fans. We are testing case cooling today.

This is what it looks like behind the motherboard try. It’s cramped and messy; but I’ve seen worse. More importantly, the cover fit without my having to hold it down like overstuffed luggage. Finally, note the margins of the CPU window. Nice and generous.

S340 Ready for Testing
S340 Ready for Testing

Populated Case
Populated Case



Intel i7 860 HT enabled, LLC enabled; ran at stock 2.93 GHz


Gigabyte GA-P55M-UD2; supplied 1.1125 volts to the CPU


4 x 2 GB G.Skill low profile DDR3-1600 at 10x (1333 MHz)

Graphics Card

PowerColor AX3450 Radeon HD 3450 (fanless) in slot 4

Solid State Drive

Kingston V+ 100 64 GB with Windows 7-64

Hard Drive 1

3.5” 1 TB Hitachi

Hard Drive 2

3.5” 1 TB Seagate

Power Supply

SeaSonic X650 650 watts


NH-D14, fanless

Stress Software

OCCT 3.10, small data set (logs temperature readings)

SSD Software

CrystalDisk Info (read after 1 hour run)

Measuring Equipment

Tenma 72-942 Sound Pressure Level Meter

Digital TEMPer USB Thermometer with dedicated logging software

The NH-D14 was installed several cases ago. That makes all the cases tested since then strictly comparable. We don’t have to worry about mount variation.

OCCT 3.10 running a small data set produces a flat core temperature curve. This produced a set of four core temps, which were automatically logged. The ambient temperature was measured with the USB thermometer and automatically logged. The temperature for the first core was averaged. The mean ambient temperature was subtracted from the mean core temperature to get the net core temperature. The mean ambient temperature was about 21 °C.

Sound Pressure Levels were measured one meter in front of the case in a basement where the ambient SPL was 30 – 31 dBA, which sounds like dead silence to the human ear. The SPL was reported both as total and as net (measured SPL minus the ambient sound level). The cases were all provided as review samples.

35S340 Testing

Let’s take a look at the S340’s results. Remember, there ain’t no free. The more a device moves air, the more noise it makes:


This little case came out tied with the Lian Li hard drive barn when it came to keeping its CPU cool. And it did this job making 3 dB less noise! It came in at second place for keeping its GPU cool, and it made about the same noise as the third and fourth place finishers in the CPU contest. Not bad at all.

But the net noise made by this case did not mean it was cooling those hard drives. You will see the result for HD #3 below, but #2 came in a degree warmer. Luckily, with an ambient of 21.6 °C, the two drives reported themselves to be running at 32 and 33 °C, which is not too hot.



The NZXT is technically a “mid-tower” case. But among mid-towers, it is a midget, standing only 18-3/4 inches tall and it is less than 7-7/8” wide. At 200 mm it has the minimum width I recommend for cases, 200 mm. Despite its reaching back only 17-1/2 inches it had room for a noise-defeating front-plate. Impressive.

Inside, the S340 NZXT manages to stuff room for three hard drives, two SSD’s and a full tower heatsink; or if you prefer, room for radiators — preferably AIO’s. That’s a lot to put into a small case like this. Yet unlike some expensive cases there is just enough room in the back for running cables behind the motherboard tray. The S340 even comes with a window to show off its contents.

Although you can stuff three hard drives into this case, will you? With the advent of high capacity hard drives, the need for more than one HD has evaporated. And because of malware that encrypts one’s system, it is no longer safe to have attached backup: the malware not only can encrypt your in-case backup, it can creep over to network attached storage (NAS) and encrypt that. Which means you must use off-site backup, like a drive you only connect for backup or a cloud-based backup service. In any case, your need for a second hard drive in a case goes away.

NZXT already anticipated that you will not be needing CD’s, since you get your software and your entertainment download from the cloud. So it left out any provision for a 5.25” device in the S340. If we stand back then, we see that this case is a thoroughly modern milly – no 5.25” device, space for only three HD’s.

You could say that this is all the case you will need. There is room for a full tower heatsink, as demonstrated by our fitting an NH-D14 in it. You can put a 240 mm or a 120 mm AIO in it.

I only have two squawks against this case: the bottom dust filter is a hindrance that you should throw away; the hard drives are passively cooled. Other than that, no problems.

With one exception, this was an easy case to work in. The PSU-HD tunnel working with the “cable management bar” obviated the need for grommets. The CPU window in the motherboard tray was generous enough to allow using any ATX or mATX motherboard. The gap in the motherboard tray for the CPU plug (EPS12V) was big enough to put it through with no problems. The only issue you will have with this case is fastening the right side screws on the hard drives, and there is a work-around for that. And that issue was made necessary by the fact that the PSU is thermally, acoustically and visually isolated by that tunnel from the rest of the case.

Overall, NZXT did a fine job of squeezing excess cost out of the S340. It is a quiet case, with no fancy features unnecessarily adding to the cost.

Speaking of cost, at the time of this writing, this case is available with window on Newegg for $70 with free shipping and at Amazon for $75 with free shipping.


NZXT S340 Pros

  • Quiet
  • Cools well
  • Small for a mid-tower
  • Nothing here that you don’t need – you don’t end up paying for fancy unnecessary features
  • PSU is thermally and acoustically isolated from the main chamber
  • PSU cables are hidden
  • A cable management bar takes away the need for grommets in the motherboard try
  • Designed to accommodate AIO’s
  • The manual is an online PDF available for download
  • No unnecessary obstructions to airflow

NZXT S340 Cons

  • The filter for the PSU is worthless
  • The right-side screws for the hard drives are a long reach

What Does This Mean? Click to Find Out!

What Does This Mean? Click to Find Out!

Ed Hume (ehume)

About Ed Hume 75 Articles
Ed Hume has been a contributor to the community for over 10 years. He has written nearly 100 reviews and guides mostly focused on cooling. His scientific and technical approach to analyzing airflow, temperatures, heatsinks and fan performance have made him a fan favorite. In one of his well-known fan roundups, he compared the performance of over 60 fans at once, now that's dedication to the craft!

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898 messages 6 likes

Definitely going to recommend this case to a few people I know who are looking to upgrade their chassis situation.:thup:

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874 messages 1 likes

It's odd: my first NZXT, in 2010, needed sticky cladding on the walls -- like this one. And the cheap grill masquerading as a dust filter was there, too; and tossed away, too. But I loved that old case. I had great fun with my old Beta Evo. This one also looks like you could have lots of fun with it.

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2,625 messages 0 likes

Ehume, nice write-up. I love mine so far, and am almost finished getting my parts together for my custom loop. :)

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2,625 messages 0 likes

It's a little rough, could've done better on the tubing I think, and still leak testing, but here is my first custom loop (ever) inside my NZXT S340!

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