SilverStone FTZ01: Mini-ITX Fortress

Table of Contents

The SilverStone Fortress FTZ01 takes the Raven RVZ01’s internal design and wraps in an aluminum exterior to create a more elegant slim mini-ITX gaming case.

August 25, 2015 by Lawrence Lee

SilverStone Fortress FTZ01
Mini-ITX Case
Street Price

Case manufacturers regularly make two or three variants of the same model, usually with minor superficial differences like adding a side window. SilverStone takes this one step further with the Raven and Fortress series. They’re usually identical on the inside but vastly different on the outside. The Raven is more budget friendly, having a primarily black plastic build on the outside, featuring beak or feather like contours. The Fortress is the more elegant but expensive alternative with a stoic, minimalist style, and clad in aluminum.

Last year SilverStone released the Raven RVZ01, the first mini-ITX member of the family, a slim vertical tower or short horizontal chassis depending on how it was oriented. It looked like a home theater enclosure, a far cry from the big towers with giant fans that made up the rest of the Raven series. But what it lacked size, it compensated with design. It was capable of housing a full sized graphics card, a 3.5 inch hard drive, a slim optical drive, and up to three slim 120 mm fans within its lithe 14 Liter body.

FTZ01, black version, unboxed.


A year later, the other shoe drops, the Fortress version of the same case, the FTZ01. Our sample is the black version but they also have a silver variant available. Again, the main difference is the external material with a single striking sculpted piece of aluminum forming the front and sides of the chassis. This is another iteration of the single U-shaped aluminum extrusion (or unibody as they like to call it) featured first in the Temjin TJ-07 of 2006 and reprised in key large cases over the years.

In the FTZ01, gone are the RVZ01’s slightly depressed sides, the feather lines, and scattered exhaust vents. The interior is the same with one minor improvement: an enlarged fan vent to support SFX-L power supplies, a variation of the SFX form factor that is 30 mm deeper, making it large enough to fit a 120 mm fan.

While these changes are minor, since I originally reviewed the RVZ01, our mini-ITX test system has been updated with more capable graphics card, a GeForce GTX 980. The FTZ01 is worthy of a retest to see if the design is truly appropriate for a compact modern high-end gaming system.



Stuffed inside the FTZ01 is a white box containing its many accessories. It ships with three ultra fine mesh dust filters, riser card, dual fan connector, the components to assemble the video card holder, case feet that are attached with adhesive for horizontal operation, and two stands for holding up the chassis in vertical orientation.

The stands are composed of two interconnecting plastic pieces that only lock when fully expanded or contracted. When wrapped tightly around the case, they’re loose with nothing to stop them from expanding outward. It’s a basic, surprising screw-up. The dust filters have magnetic strip applied only to one side, so they need to be turned the right way to stick.

Specifications: SilverStone Fortress FTZ01
(from the
product web page
Model No. SST-FTZ01B (black)
SST-FTZ01S (silver)
Material Aluminum unibody frame, steel chassis
Motherboard Mini-DTX, Mini-ITX
Drive Bay External Slim slot-loading optical x 1
Internal 3.5” x 1, 2.5” x 3
Cooling System Top 1 x 120mm fan, 1500rpm 18dBA
Bottom 1 x 120mm fan, 1500rpm 18dBA
1 x 120mm fan slot
Expansion Slot 2
Front I/O Port USB 3.0 x 2
audio x 1
MIC x 1
Power Supply SFX, SFX-L
Expansion Card Support graphics card up to 13”, width restriction – 5.88”
Limitation of CPU cooler 83mm
Net Weight 4.6kg
Dimension 376mm (W) x 107mm (H) x 351mm (D), 14 liters
Extra Support Kensington locks


The Fortress FTZ01 is steel case with a single piece of extruded aluminum forming the sides and top. Its dimensions are 37.6 x 10.7 x 35.1 cm or 9.1 in x 14.8 in x15.6 (W x H x D), for a total volume of just 14.1 Liters. It’s one of the smallest mini-ITX cases on the market that can accommodate a full length graphics card.

The sides of the case are aluminum with a wide band wrapped around the center, separating the USB 3.0 and audio ports from the HD/power LED/buttons at the front/right of the case.

The band around the middle also separates ventilation ports along the sides of the case.

The stock fans blow into the system, creating a positive-pressure airflow system. The larger honeycomb grills located at the rear serve as primary points of exhaust. The AC power plug is located in the bottom/right corner just below where a dual slot video card can be installed in a horizontal position, connected via riser card.

The intake vents are located on the underside with a large grill stamped out for the power supply and more stylish 2 x 120 mm fan ports underneath the video card area. Two slim 120 x 15 mm fans are included, one positioned here, the other on the top of the case over the CPU.

With a thickness of 0.8~0.9 mm, the top cover is fairly well constructed. To ensure it fits snug with the chassis there are two guides at the sides and three tabs at the front. Only two screws secure it at the back.


The interior is essentially a single space with a few removable parts. A slim optical drive and two 2.5 inch drives can be mounted to a large plastic bracket occupying the left half of the case. The video card also installs to this contraption; the bracket is also attached to the metal expansion slots at the back. The motherboard is positioned on the right side along with a power supply cage that can also accommodate a 3.5 inch drive on top.

The interior.

GPU/drive assembly.

With the bracket out of the way, you can see a side-mounted 2.5 inch drive tray toward the front and the two fan positions underneath the video card. Standard 25 mm thick fans can probably be used but they may press directly against the fan(s) on the video card, creating turbulent noise.

The side ventilation holes on the interior are much larger than those on the outside.

The power extension cable stays neatly out of the way, snaked along the edge of the chassis to the back port.

The stock fan sports a similar design to Scythe’s slim models with a support ring between the hub and the frame edge. The blades themselves also have a matching ring structure.


The assembly process is not too difficult as the modular nature of the case helps alleviate the inherent issues of putting together a system in a cramped space. Installing the video card is the hardest part as the riser card has to go into the slot and the rest of the assembly has to be attached at two different spots. It takes some work to get the fit right with a larger video card and you can’t handle it with too much force due to the plastic construction. Cabling can also be an issue, especially when using a CPU heatsink with a wide footprint. To make things a little easier, all the plugs on the motherboard should be connected before mounting the board.

The power supply frame with our 3.5 inch Seagate 2TB SSHD and SilverStone 500W SFX-L power supply screwed in.

Asus Strix GTX 980 secured to the VGA mount.

To prevent the GPU from drooping, a support structure is provided but it doesn’t fit properly on our card. The fan shroud is so wide that the portion attached to the mounting bracket can only be fitted near the exposed heatpipe. This same heatpipe prevents the second piece from making a connection. If this is a concern, you may want to use zip-ties to hold it up.

Our test system fully installed. The Noctua NH-L12 heatsink is short enough if the top 120 mm fan is removed (there’s a 92 mm fan underneath the fin-stack). The tips of the heatpipes come intimately close to contacting the riser card.

The power supply frame is not flush with the front of the case, creating a gap that can be used for hiding excess cabling. Almost all the wiring will wrap around the PSU.

There is 19 mm of clearance above the NH-L12 so the fan on the top cover is only 4 mm away, and will act as a second CPU fan.

The top fan vent position covers most of the heatsink, so this should be an effective CPU cooling combination.


System Configuration:

  • Intel Core i5-4690K processor – 3.4 GHz (3.8 GHz with Turbo
    Boost), 22nm, 84W
  • Noctua NH-L12 CPU cooler – 92 mm fan only
  • ASUS Z97I-PLUS motherboard – Intel Z97 chipset, mini-ITX
  • ASUS Strix GeForce GTX 980 graphics card – 2048 CUDA cores, 1178
    MHz clock (1279 MHz with GPU Boost), 7010 MHz memory
  • Kingston HyperX Genesis memory – 2x4GB, DDR3-1600, C10
  • Seagate Desktop SSHD hybrid drive – 2TB, 7200 RPM, 8GB NAND
    Flash, SATA 6 Gbps
  • SilverStone SX500-LG power supply – 500W, modular, SFX-L
  • Microsoft
    Windows 7 Ultimate
    operating system, 64-bit

Measurement and Analysis Tools

  • Prime95
    processor stress software.
  • FurMark
    stability test to stress the integrated GPU.
  • Asus GPU Tweak to monitor GPU temperatures and adjust fan speeds.
  • SpeedFan
    to monitor system temperatures and adjust system fan speeds.
  • Extech 380803 AC power analyzer / data logger for measuring AC system
  • PC-based spectrum analyzer:
    SpectraPlus with ACO Pacific mic and M-Audio digitalaudio interfaces.
  • Anechoic chamber
    with ambient level of 11 dBA or lower

Testing Procedures

The system is placed in two states: idle, and load using Prime95 (2/4 instances, large FFTs setting) and FurMark, an OpenGL benchmarking and stability testing utility. This puts more demand on the CPU and GPU than any real life application. Throughout testing, system temperatures, noise levels, and power consumption are recorded. During the load test, the system and GPU fans speeds are adjusted to various levels in an attempt to find an optimal balance between cooling and noise while maintaining a GPU temperature of 85°C (at an ambient temperature of 22°C).

Baseline Noise

For our baseline noise tests, the system is left idle, the CPU fan is set to its minimum speed under PWM control (400 RPM), and the GPU fans are off by default. The system fan(s) are connected to controllable fan header(s) and are set to a variety of speeds using SpeedFan. This gives us a good idea of what the stock fan(s) sound like at different speeds with minimal interference from other sources.

Baseline Noise Level
(Idle, CPU fan at 400 RPM, GPU fans off)
Fan Setting
Avg. Fan Speed
SPL @1m
15~16 dBA
880 RPM
17~18 dBA
1040 RPM
20 dBA
1170 RPM
22~23 dBA
1320 RPM
25 dBA
1550 RPM
29~30 dBA
Measuring mic positioned 1m at diagonal angle left/front
of case in vertical orientation (top fan facing mic).
Ambient noise level: 10~11 dBA@1m.

The stock fans are thin models with slimmer blades so they don’t produce as much noise as standard 25 mm thick fans, but their relatively high nominal speed makes up for this. As a result, they should satisfy both the quiet conscious and the noise tolerant. At idle, the rest of the system measures 15~16 dBA@1m and the system fans start to make an acoustic impact at about 800 RPM. At full speed, they’re fairly loud, generating 29~30 dBA@1m.

The quality of noise output is high. There is a bit of drive vibration but the effects are not noticeable from a nominal distance, and the stock fans have a pleasant sound. They have a mostly broadband profile with a notable lack of tonality. This is rather surprising as the RVZ01, which is equipped with the same fan, was plagued with buzzing and clicking, and one of its fans was faulty and had to be replaced. After hearing the fans in this case, it now seems possible that the second fan in the RVZ01 was also faulty.


System Measurements: Prime95x2 + FurMark,
85°C Target GPU Temp (at 22°C Ambient)
Avg. System
Fan Speed
880 RPM
1040 RPM
1170 RPM (70%)
1320 RPM (80%)
GPU Fan Speed*
1700 RPM
1260 RPM
1210 RPM
1080 RPM
CPU Temp
MB Temp
System Power (AC)
28 dBA
24~25 dBA
25~26 dBA
27 dBA
*set as low as possible to maintain target GPU temperature on load.
CPU fan at 50% (1000 RPM).
Ambient temperature: 24°C.

For loading testing, the Noctua NH-L12 heatsink’s 92 mm fan was set to 50% (1000 RPM), a speed that provides a decent amount of CPU cooling without having a large impact on the noise level (it measured just 16 dBA@1m at this speed). Of the system fan speeds tested, the 60% level delivered the lowest overall sound output with our testing parameters (adjusting the GPU fan speed to maintain a 85°C GPU temperature at 22°C ambient). At the 50% level, the stock fans were fairly ineffective, requiring a much higher GPU fan speed, and causing substantially higher CPU and motherboard temperatures. The 70% and 80% settings ultimately created more noise than they saved.

On load, the system sounds almost as it did during the baseline tests. The CPU fan was set to a higher speed but its smooth profile made it inconspicuous. I’m not sure if the power supply fan spun up from its minimum speed, but its contribution went unnoticed. The GPU fans made the most impact but they sound fairly good spinning only 160 RPM faster than the minimum. It also helps that they were positioned on the opposite side of the microphone. The machine measures 1~2 dB higher on the other side.

System Measurements: Prime95x2 + FurMark
filters removed
filters removed, horizontal
Avg. System
Fan Speed
1040 RPM
880 RPM (50%)
1320 RPM (80%)
GPU Fan Speed
1260 RPM
1070 RPM
1750 RPM
CPU Temp
MB Temp
GPU Temp
System Power (AC)
24~25 dBA
23~24 dBA
31~32 dBA
CPU fan at 50% (1000 RPM).
Ambient temperature: 24°C.

Removing the impedance caused by the filters resulted in a moderate increase in thermal performance. Using the same fan speeds as the best result achieved earlier, taking the filters out of the equation allowed temperatures to drop across the board, with the most noticeable improvements being a 5°C and 6°C decrease for the CPU and GPU respectively. The system fans can thus be slowed from 60% to 50% and the GPU fans can be turned down from 43% to 40% while maintaining the same GPU temperature standard, for a net noise difference of just 1 dB.

The best result I could achieve with the case in horizontal position was 31~32 dBA, with the stock fans at 80% and GPU fans at 53%. It was significantly louder than the vertical orientation as the fan vents become more restricted. Even with the filters removed, much higher fan speeds are required to attain a similar level of cooling.


Case Comparison: Prime95x2 + FurMark
(85°C GPU Temp at 22°C Ambient)
BitFenix Prodigy Black
SilverStone FTZ01
Fractal Design Node 202
Phanteks Evolv ITX (front panel removed)
Phanteks Evolv ITX
CPU Cooler
Scythe Mugen Max at 500 RPM
Noctua NH-L12 at 1000 RPM
Noctua NH-L9i at 2490 RPM
Scythe Kotetsu at 900 RPM
System Fan Speed
500 RPM
(2 x 60%)
1040 RPM
(2 x 60%)
620 RPM
(1 x 80%)
GPU Fan Speed*
880 RPM
1260 RPM
2930 RPM
1130 RPM
1670 RPM
CPU Temp
MB Temp
20~21 dBA
24~25 dBA
41~42 dBA
25~26 dBA
29 dBA
Apx. Case Volume
26.4 L
14.1 L
10.2 L
34.1 L
Ambient temperature: 22°C.

Considering the relative size of the FTZ01, its performance is
impressive. Though substantially louder than our Mini-ITX
Gaming Build
using the BitFenix Prodigy, that system was tuned to achieve
the lowest noise level possible. The higher fan speeds required to attain a
similar amount of CPU/motherboard cooling may result in the noise difference
being cut slightly.

Fractal Design’s
Node 202
is actually more similar to the FTZ01 than any other competitor,
though it is smaller, but its performance is far worse, hobbled by poor ventilation
and a lack of fans. It could not operate the ASUS Strix 980 at the target
85°C temperature, and in fact failed to keep the card from throttling, even with its fans going ballistic. Ditto the fan
on the smaller CPU cooler, which explains the very high 41~42 dBA @1m SPL.

Also plagued by airflow problems, the Enthoo
Evolv ITX
was 4~5 dB louder and hotter by double-digits inside under
the same test parameters. Even with its entire front panel ripped off, it doesn’t
quite match up to the FTZ01.


These recordings were made with a high resolution, lab quality, digital recording
system inside SPCR’s own 11 dBA ambient anechoic chamber, then converted to
LAME 128kbps encoded MP3s. We’ve listened long and hard to ensure there is no
audible degradation from the original WAV files to these MP3s. They represent
a quick snapshot of what we heard during the review.

Each recording starts with ambient noise, then 5~10 second segments of product
at various states. For the most realistic results,
set the volume so that the starting ambient level is just barely audible, then
don’t change the volume setting again while comparing all the sound files.


The Raven RVZ01 was a hit for SilverStone, a small slim case that makes efficient
use of the space allotted. The Fortress FTZ01 brings SFX-L power supply support
and a stunning unibody aluminum construction to the table (although in my view,
the silver color version shows off that prime feature far more attractively).
With our newer, more powerful mini-ITX test system, the design holds up well.
It offers gamers a reasonably quiet, compact alternative to the more bulky and
boxy enthusiast cases as long as it’s positioned upright. There are actually
no other cases of the FTZ01’s size and shape which can match its performance
at this time.

Silver and black versions of the FTZ01 compared: It’s your choice.

In terms of component selection, The FTZ01 is not as flexible as larger cases,
but it should satisfy the needs of most users. Drive support is a concern only
if you horde data and don’t have another PC or NAS on the network for your storage
needs. For everyone else, the single 3.5 inch and three 2.5 inch drive bays
are sufficient. While ATX power supplies are off the table, Silverstone’s own
SFX models offer enough power to supply any single GPU configuration. By my
measurements, CPU cooler height is limited to 85 mm (70 mm plus the top fan),
but with a decent heatsink, this shouldn’t be an issue.

Complaints are relatively few and minor. I loathe the plastic stands to hold
the case vertically as there’s nothing to stop the pieces from sliding away
from one another. I would suggest taping or gluing them together to reduce the
chance of the chassis being accidentally knocked over. Fitting the GPU bracket
can be a pain, especially with larger cards, but thankfully this won’t have
to be performed more than once or twice. In addition, the contraption for keeping
the card from drooping may not fit on wider video cards.

The SilverStone FTZ01 is currently selling for US$130, about US$50
more than the RVZ01. If you’re in the market for a slim gaming tower, either
would do nicely. In terms of value, you can’t beat the RVZ01, but if you’re
turned off by the Raven’s plastic avian-themed exterior, the Fortress’ elegant
aluminum styling may be worth the premium. The Milo ML07, a third variant of the same chassis, is also a viable alternative priced at around US$70. It has a plastic exterior with a reserved look featuring boxy contours but doesn’t ship with any fans.

Our thanks to SilverStone
for the Fortress FTZ01 case sample.

The SilverStone Fortress FTZ01 is recommended by SPCR

* * *

Articles of Related Interest
Fractal Design Node 202 Compact Gaming Case
Phanteks Enthoo Evolv ITX Mini Tower
SilverStone RVZ01: A Mini Raven
Quiet Mini-ITX Gaming Build Guide #3: BitFenix Prodigy Edition
Quiet Mini-ITX Gaming Build Guide #2: NCASE M1 Edition
Quiet Mini-ITX Gamer Build Guide

* * *

this article in the SPCR Forums.

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