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
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.
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
product web page)
|Model No.||SST-FTZ01B (black)|
|Material||Aluminum unibody frame, steel chassis|
|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
|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|
|Dimension||376mm (W) x 107mm (H) x 351mm (D), 14 liters|
|Extra||Support Kensington locks|
EXTERIOR & SIDE PANELS
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 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 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.
Measurement and Analysis Tools
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).
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)
Avg. Fan Speed
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)
1170 RPM (70%)
1320 RPM (80%)
GPU Fan Speed*
System Power (AC)
*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, horizontal
880 RPM (50%)
1320 RPM (80%)
GPU Fan Speed
System Power (AC)
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
Fractal Design Node 202
Phanteks Evolv ITX (front panel removed)
Phanteks Evolv ITX
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
(2 x 60%)
(2 x 60%)
(1 x 80%)
GPU Fan Speed*
Apx. Case Volume
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.
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
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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
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