Phew. It’s been a while since I’ve done one of these. We have a new guy, Jeff Kampman, doing case reviews for us now (and nailing it), so I’ve been keeping busy with other things. Jeff is occupied with another project at the moment, though, so I figured I’d give Cooler Master’s Silencio 652S a spin myself.

The Silencio 652S has been around for a little while, and it remains an interesting option—particularly as we consider new case picks for our System Guide. Priced at $119.99 (or $99.99 after a mail-in rebate), this enclosure can play host to an ATX motherboard along with a generous assortment of storage drives and cooling contraptions. The Silencio 652S also features noise-dampening foam on its front and side panels, and it ships with plastic covers to block unused vents.

The result, then, should be a relatively roomy and cool-running enclosure that still satisfies the needs of silent-PC connoisseurs. For 100 bucks after rebate, that’s not a bad proposition.

Externally, the Silencio 652S looks pretty slick and stealthy. It combines black steel and matte black plastic in the same way as many of today’s popular cases.

Unlike some of those offerings, however, the Silencio 652S doesn’t leave any of its front, side, or top vents uncovered. The front vents are hidden behind a door, and the side and top vents are covered with removable plastic covers. The only visible intake vents are the little horizontal slits along the sides of the front bezel. When the door is closed, intake airflow is directed through these openings.

Keen-eyed readers may find this case looks familiar. That’s because the Silencio 652S is visually identical to the older Silencio 652. As far as I can tell, the main difference between the two models is the use of newer Silencio FP 120 fans on the 652S. Cooler Master claims these fans deliver “absolute silence and excellent airflow.” Together with the foam-lined panels, they should help keep noise levels to a minimum.

This reverse-angle shot gives us a glimpse at the Silencio 652S’s internal layout. We can see the power supply is supposed to sit at the bottom, while the motherboard isn’t meant to be mounted upside down or in some other crazy position.

Users with exotic liquid-cooling setups will be happy to find three rubber-grommeted holes beneath the 120-mm exhaust fan. Further down, you’ll notice an extra expansion slot cover that sits perpendicular to the main expansion slots.

The purpose of that extra slot cover should be obvious to anyone whose motherboard shipped with an expansion slot bracket for extra USB, FireWire, or audio ports. Such brackets often plug right into the motherboard’s internal headers, so there’s technically no need for them to block a PCI or PCIe slot. With the Silencio 652S, they don’t have to (unless you have more than one, I guess).

Cooler Master Silencio 652S Dimensions (H x W x D) 20″ x 8.7″ x 20″ Supported motherboards microATX, ATX 3.5″ drive bays 9 2.5″ drive bays 10 5.25″ drive bays 3 Fan mounts 8 Included Fans 2x 120-mm front intake 1x 120-mm rear exhaust Front panel I/O 2x USB 3.0 2x USB 2.0 Headphone Microphone SD card reader Max. graphics card length 10.6″, 12″, or 15.4″, depending on drive bay config Max. CPU cooler height 6.9″ Gap behind motherboard 0.7″

We’ll start our dissection of the Silencio 652S shortly. First, here’s an at-a-glance overview of the case’s specifications.

This table doesn’t show us anything particularly shocking or unusual, except perhaps for the number of 2.5″ and 3.5″ drive bays. Okay, so the Silencio 652S doesn’t really have 19 internal drive bays. As we’re about to see, the seven side-mounted bays at the front can be configured to accommodate either 3.5″ or 2.5″ drives. Users can also mount 2.5″ drives to the inside of the bottom panel, to the back of the motherboard tray, and to the bottom of the lowermost 5.25″ bay.

One last point of note: the 0.7″ clearance behind the motherboard tray also looks potentially tight, at least compared to the recent Corsair enclosures we’ve tested. The similarly priced Obsidian 450D has 0.8″ of space back there, and that’s without acoustic foam eating into it. We’ll see in our assembly section how that difference affects cable management.

A closer look at the outside

In a nod to those of us who keep our PCs under our desks, the Silencio 652S sticks its front-panel I/O up top. The power and reset buttons are on the edge of the front bezel, though.

We’ve got four USB ports (two SuperSpeed and two regular), mic and headphone jacks, an SD card reader, and a Cooler Master logo that looks like it should light up but actually doesn’t. The only LEDs are on the front panel. The power LED is embedded in the power button, and the storage activity LED sits just below it.

Here’s the Silencio 652S with its top, side, and front vents laid bare. The top cover simply slides off, but the side cover is kept in place by a couple of screws. Undoing those requires removing the side panel.

As for the front door, a simple magnetic latch keeps it shut. The door can also be removed, but that involves taking off the entire front-panel assembly and pulling out the pegs that hold the hinges together. Honestly, I’m not sure why anyone would bother. The front door is one of the Silencio 652S’s selling points, since it’s lined with acoustic foam. Thanks to all the venting along the sides, I doubt it impedes cooling performance much, if at all.

Here’s the acoustic foam that lines the front door. The foam spans the door’s entire height, and it feels soft and rubbery. From what I can tell, it’s about two millimeters thick.

In its default configuration, with two pre-installed 120-mm fans up front, the Silencio 652S directs intake airflow through a removable dust filter. The filter is kept in place by a single plastic latch at the top, so it’s painless to pop off and vacuum (or shake off outside, if the wind is right).

The side panels are also lined with foam, but the foam here is about half as thick, and it’s made of a different material. It feels a lot more rigid, and the texture isn’t the same.

That completes our external tour. Read on for a look at the Silencio 652S from the inside.

Diving in

Now, ladies and gentlemen, the moment you’ve all been waiting for: the Silencio 652S’s innards laid bare for all to behold!

At first glance, these innards look pretty unassuming. You’ve got your black paint job, bottom PSU mount, sideways drive bays, and motherboard tray with the requisite cut-outs for cable routing and access to the CPU cooler backplate. Pretty much every mid-range enthusiast case looks like this nowadays, and that’s a good thing. Cooler Master shouldn’t be chastised for sticking with what works.

The Silencio 652S doesn’t stick to the formula in every respect, though.





Cooler Master houses the seven internal drive trays in two cages. Both cages can be removed, and the top one can also be widened to accommodate 3.5″ drives.

Widening the top cage is surprisingly easy. Simply pop the drive trays out, undo the three screws that hold the cage’s inner wall (to the left of the picture above) in place, and then reposition the wall and put the screws back in. The trays can be widened to fit.

Yes, the Silencio 652S’s drive trays have the unusual ability to shape-shift. They’re made up of two sliding plastic pieces that lock into one of two positions, to accept either 3.5″ or 2.5″ drives. The trays can also stretch beyond their 3.5″ position to allow mechanical hard drives to snap on more easily. I haven’t encountered this design anywhere else, but it’s very clever, and I hope more case makers adopt it. My only gripe is that, even in the 2.5″ position, the trays don’t have a tool-less mounting mechanism for 2.5″ drives. You’ll have to screw in your SSDs by hand.

These drive trays also have little flaps that swing out on either side to keep SSDs steady while you’re screwing them in. Also, the trays have screw holes on the bottom, so even in their 3.5″ position, they can house 2.5″ drives. That arrangement doesn’t require you to remove the metal studs along the sides, either, unlike on Corsair’s drive trays.

There isn’t a lot happening on the Silencio 652S’s right side. You can see the cable-routing holes, some of the as-yet-unrouted cables, and the lone 2.5″ drive bay on the back of the motherboard tray. This isn’t so much a drive bay as a set of holes into which a drive can slide, provided it’s got the right combination of screws and rubber grommets fastened to it. This bay can be populated without the motherboard needing to be removed, by the way.

This bottom view shows us the last two of the Silencio 652S’s removable fan filters: one under the power supply’s intake vent and another under the bottom 180-mm vent, which is empty by default. The 180-mm vent also has mounting points for another 2.5″ drive, if you’re really hard up for space.

The case’s 120-mm rear exhaust fan and 240-mm top radiator mount can also be seen from this angle. Note that the 120-mm fan is the only exhaust, which means the case should have more air coming in than going out by default. That’s a good thing. If air pressure inside the case is positive, and intake air is shepherded through filtered vents, then dust shouldn’t get sucked in through unfiltered cracks.

As for the top radiator mount, that area can also play host to a couple of 140-mm fans or a single 180-mm spinner. No matter what you put up there, though, you’ll have to take off the case’s top plastic cover. Unlike the front door, the top cover lacks venting.

The assembly

Building a PC inside the Silencio 652S is an uneventful process—for the most part.

The case is relatively roomy, and all of the various bits and pieces fit together without coaxing. I did need to install motherboard standoffs myself, though, and as I noted on the previous page, solid-state drives can’t be snapped on. They have to be screwed in.

I didn’t hit any snags until I got to cable routing. Therein lies what, in my view, is the Silencio 652S’s biggest weakness. The clearance behind the motherboard tray is just too tight.

Routing the cables through the holes around the motherboard didn’t take too much work, although the holes are somewhat small and close to the circuit board. Once the cables poked out on the other side, however, I had to route them very carefully so as not to prevent the side panel from sliding back on. I was pretty much forced to use cable ties, which I usually dispense with for case reviews. Then, even after careful routing (and re-routing, and re-re-routing), the side panel wouldn’t go on until I laid the case flat on its side and pushed a little.

Perhaps I could have arranged the cables in a better, slightly more efficient way. The picture above does show some of the SATA and power cables overlapping. That overlap was difficult to prevent, though, since the system’s Blu-ray drive needed its own SATA power lead. Keep in mind that this build only has one hard drive, one SSD, and a single graphics card. A beefier storage setup and multiple GPUs would entail more data cables and power leads, at which point overlapping would be all but unavoidable.

I was able to mitigate the problem by letting more cables poke into the main compartment than I usually would, without putting them directly in the path of airflow. Still, I don’t recall ever having to work so hard to get cables organized in an enthusiast enclosure of this caliber. Even the $60 Carbide Series 200R from Corsair was better in that department.

I suspect part of the problem may lie with the foam on the right side panel, which effectively reduces clearance by a millimeter or so. The motherboard tray is awfully close to the edge of the case to begin with, though. Cooler Master could easily have added another quarter inch of space there without increasing the Silencio 652S’s bulk by very much. I’m not sure why they didn’t, because this case is clearly designed to house large storage arrays. What’s the use of all those drive bays if space for power and data cables is so limited?

Our testing methods

Here are the components we used:

Processor Intel Core i7-2600K Motherboard Asus P8Z77-V LE Plus Memory 4GB Kingston HyperX DDR3 SDRAM at 1333MHz Graphics card XFX Radeon HD 7870 Black Edition Sound card Asus Xonar DG Storage Samsung 830 Series 128GB Samsung Spinpoint F3 1TB Asus Blu-ray combo Power supply Corsair HX750W 750W CPU cooler Thermaltake Frio OS Windows 8 Pro

We’d like to thanks Asus, Corsair, Kingston, Intel, Samsung, Thermaltake, and XFX for supplying all this excellent hardware.

We tested using the following applications:

The tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to discuss them with us.

Temperatures and noise levels

We used AIDA64 to keep track of temperatures for individual system components (the processor, GPU, motherboard, and storage drives) throughout a 40-minute period. Ambient temperatures were consistent to within about 2°C during testing.

We started by leaving the system idle at the Windows 8 desktop for 10 minutes. We then fired up the Heaven GPU benchmark and left it running by itself for 10 minutes. Next, we added a Prime95 CPU torture test to the mix and left it running, together with the Heaven benchmark, for 10 minutes. Finally, we stopped both tests and let the system cool down for the final 10-minute stretch.

Now, a small caveat. The Silencio 652S’s rear exhaust fan came apart during shipping. Cooler Master sent us a replacement fan, but it was a higher-speed model. We were able to make up most of the speed difference using Asus’ Fan Xpert utility, but the replacement spun slightly faster than the others at idle: roughly 800 RPM instead of 630-670 RPM. The effect on temperatures should be negligible, but it’s worth mentioning.

Here are the results plotted over time. You can click the buttons below the graph to see temperatures for the different components. We used Corsair’s Obsidian 750D to provide a frame of reference, but keep in mind that it’s a more expensive case the Silencio, at around $160.





The Silencio 652S does a nice job of keeping our hard drive, solid-state drive, and motherboard cool. CPU and GPU temperatures are a little higher than in the Corsair enclosure, though.

The plots above depict broad trends, but we can also show you some exact numbers. The bar chart below shows the minimum temperatures from the idle and cooldown parts of the run, and it also shows the highest temperatures recorded during the two load tests.





Under a full load, peak CPU and GPU temps were 4-5°C higher in the Silencio. Unless you plan to push components to their thermal limits, those differences shouldn’t rule out higher overclocks. They may cause CPU and GPU fans to spin up slightly faster, though, which could translate into slightly more noise.

Speaking of which, let’s have a quick look at noise levels. As always, we used our TES-52 digital sound level meter to measure sound pressure. The noise floor in my office was around 40 dB. (Yes, I need to move somewhere quieter.)





The Silencio 652S registered lower noise levels than the Obsidian 750D according to our sound level meter. That’s no doubt thanks to the acoustic foam and those plastic covers, which we left on during our testing.

While the numbers suggest the Silencio is quieter, I found the character of its noise a little less palatable than the Obsidian’s. The culprits seemed to be Cooler Master’s Silenco FP 120 fans, which produced a faint but audible hiss at low speeds. That hiss turned into a distinct hum when the fans revved up. I thought the noise came from the system’s graphics card at first, but it stopped when I pushed down on the spindles of the Silencio’s two front fans. I was able to repeat the effect with the rear spinner, too.

Too bad, because the case really does a fine job of muting vibrations from the CPU and GPU fans.