Rosewill Legacy U3 Aluminum MicroATX Tower

Table of Contents

While limited in expansion capabilities with just a single 120mm fan for airflow, the Rosewill Legacy U3 is compact for a microATX tower, and sports a pleasing all-aluminum exterior.

September 29, 2014 by Lawrence Lee

Rosewill Legacy U3
MicroATX Case
Street Price

MicroATX is overshadowed in the DIY community by ATX, despite often being the
more pragmatic choice as users often use few if any of the extra expansion slots
afforded by ATX. While technology is constantly getting smaller, to the point
where some users have ditched their tower PCs altogether, microATX continues
to play second fiddle in the world of desktops. This is reflected in the range
of cases available, with most microATX models being plain generic towers from
budget/OEM manufacturers. There are a few handsome and enthusiast models but
the choices pale in comparison to the multitudes produced for ATX. The market
has apparently determined that microATX simply isn’t sexy.

One case seeking to dispel this notion is the Legacy U3, a model produced by
a surprising source: Rosewill, which began as the house brand of Newegg.
Store brand technology products are often regarded as cheap/unreliable, but
Rosewill has developed a fairly solid reputation among Newegg patrons.

The Legacy U3.

One advantage of cutting out the middle man is lower pricing, with the Legacy
U3 selling for a mere US$90, a bargain for an all-aluminum tower. The
front of the case is striking as its brush aluminum facia is bereft of ventilation,
drive bays, or even a single crease of any kind, and the gentle curves at the
top and bottom are a refreshing change from sharp corners. The rather low position
of the front audio and USB 3.0 ports wouldn’t be ideal if the case were placed
on the floor, however. The side window is more attractive than most, as it takes
up almost the entire side panel, is more or less centered, and hasn’t been fashioned
into a weird/angular shape. Overall we’d have to say this is one of the most
elegant microATX case we’ve come across, with a sleeker exterior than the stoic
aluminum-clad fare from manufacturers like SilverStone and Lian Li. Along with
our sample black model , a Silver edition is also available.

Since this article was posted, SPCR forum members have shared information
about the origins of this case:

“These are Jonsbo cases with a Roswell badge. They come in two
other sizes as well.

“They are also available under the Cooltek label, and probably

“In North America, Rosewill is the exclusive Jonsbo distributor,
selling their products under its own brand, while, with a similar arrangement,
Cooltek is the exclusive Jonsbo distributor in EU.”


Specifications: Rosewill Legacy U3
(from the
product web page
Model Legacy U3-B (black), U3-S (silver)
Type MicroATX Mini Tower
Color Black
Case Material Aluminum Alloy
With Power Supply No
Motherboard Compatibility M-ATX / ITX (within 245mm x 245mm)
With Side Panel Window No
Internal 3.5 Drive Bays 2
Expansion Slots 4
Front Ports 2 x USB 3.0 Ports Audio In/Out
120mm Fans 1
Side Air duct No
Dimensions 8.19″ x 10.63″ x 14.13″ (W x D x H)
(0.47″ feet not included)
208 x 270 x 359 mm (W x D x H)
20.4 liters (12mm feet not included)
Weight 5.51 lb. / 2.5 k.g

No case is without its drawbacks and the U3’s derive mainly from its size.
It is small for a microATX model, standing just 35.9 cm (14.1 inches) tall and
measuring 27.0 cm (10.6 inches) from front to back, just over 20 liters volume.
Most microATX cases are closer to 30 liters and many are far larger than that.
While a tall/shallow shape is favored for larger NAS systems, the U3’s drive
support is limited to just 2 x 3.5 inch or 1 x 3.5 inch + 2 x 2.5 inch drives,
and optical storage is off the table completely. The short depth rules out long
graphics cards with the specified limit being 26.0 cm (10.2 inches). Cooling
may also be an issue as there’s only one fan position, the front bezel is completely
solid, and the power supply is positioned at the top of the tower and must draw
air from inside the case. To help increase airflow, ventilation has been provided
along the sides and underneath the case. The stock fan is a relatively quiet
120 mm model connected to a two-speed fan control switch.

The box.


As befits an online house brand case, the packaging is very plain with the
case shipping in a basic cardboard box unmarked with adornments aside from the
brand and name. The accessory box contains the necessary screws, long motherboard
standoffs (three of which are plastic), rubber grommets to dampen hard drives,
zip-ties, a PSU support bracket, a PC speaker, and an assembly manual.


As the Legacy U3 is a small aluminum case with a mostly empty interior, it
weighs just 2.5 kg or 5.5 lb. Excluding the case feet, it measures 20.8 x 27.0
x 35.9 cm or 8.2 x 10.6 x 14.1 inches (W x H x D), a total volume of just over
20 liters.

As the front face is completely solid, vents running along the sides provide much needed airflow.

Looking at the back we can see the top-mounted power supply position, a 120 mm exhaust fan with a fine mesh filter, and a small fan control switch. There’s only one removable side panel; the left/rear sides appear to be one piece as well as the top/front/bottom.

The case utilizes conventional rubber case feet with silver outer rings to add some shine. The bottom of the case is heavily ventilated and serves as a home to either one 3.5 inch or two 2.5 inch drives.

The side panel is a respectable 1.4 mm thick and features a large side window. The rear of the panel is curved to match the rest of the case.

Usually side panels have metal tabs that hook onto holes on the
edge of the chassis but the Legacy U3 instead uses a less conventional
barb system, and the fit is relatively secure.


There’s little to say about the quality of the internal construction, as it’s
mostly an empty space created by the enclosing panels. It’s reasonably well-built
for a small all-aluminum chassis. Aside from the drive mounts, the layout is
very simple and traditional, with the power supply at the top back corner. Compared
to a bottom-mounted PSU case, the CPU and PSU tend to be subject to more thermal
stress than the GPU.

A second 3.5 inch drive mount is available on a bracket attached to the bottom of the case with four screws.

When using the frame, the drive is secured from the side rather than from underneath.

The interior is cramped — a microATX board occupies almost
all the available horizontal space. The two pieces that seem to make
up the bulk of the chassis are affixed to each other with screws running
along the inside.

The included fan is a relatively slow 1100 RPM model with a short
3-pin connector that connects to a small fan controller underneath it.
The controller has three settings, low, off, and high (the off position
is located in the center) and powered with a 4-pin molex connector.

With no direct airflow coming in from the front, the bottom panel
as well as all the expansion slot covers are heavily ventilated.


Assembling a system inside the Legacy U3 is straightforward, but the compact
dimensions aren’t ideal for the clumsy or thicker-fingered. Putting everything
together is somewhat challenging, especially if a microATX motherboard is used,
as the entire case itself is not much deeper than the width of the board.

A support bar, attached with three screws, is provided to help hold up the power supply.

According to our measurements there is space for a 26.4 cm graphics
card, but the actual limit is lower due to geometry. Longer cards have
to angled in so it was a tight fit even to get our 24.1 cm long HD 6850
in position. The location of the PCB for the front ports doesn’t help

Cabling was less of an issue than expected. The only places to tie
down cables are the side and bottom air vents, but we managed to push
almost all the wiring toward the front. Still, a modular power supply
is highly recommended.

With the side panel on, little cabling is visible from the outside.

Placing a 3.5 inch drive at the bottom of the case limits the amount
airflow to the graphics card. A drive here cuts off much of the ventilation
via the floor and leaves only a small gap between it and the GPU.

Alternatively, you can mount the drive on the side bracket, but this can interfere with larger CPU coolers. Our Noctua NH-U12P was too wide; by our measurements, a 92 mm fan model would be required if you want a tower heatsink that blows toward the back of the case.

We opted to test the system with both hard drive positions. For the side placement, we rotated the CPU cooler and moved the fan to the top in order to accommodate the drive bracket.

The power LED is a blue ring around the power button. When the hard
drive is active, a smaller red LED comes on, giving it a purplish tinge.


System Configuration:

Measurement and Analysis Tools

System temperatures and noise levels were recorded with SpeedFan and GPU-Z
at idle and on load using Prime95 (large FFTs setting) and FurMark, an OpenGL
benchmarking and stability testing utility.

Baseline Noise

Baseline Noise Level (dBA@1m)
Controller Setting
Fan Speed
SPL @1m
560 RPM
12 dBA
1100 RPM
20 dBA
Measuring mic positioned 1m at diagonal angle left/front
of case.

The Legacy U3 is equipped with a single 120 mm exhaust fan with a nondescript
design, and a basic fan controller with two speeds and an off switch. The stock
fan is a slow model: 1100 RPM on high speed and a mere 560 RPM on low. On low,
it generated an SPL of just 12 dBA@1m, which is quieter than most noise-producing
components. On high, it emitted 20 dBA@1m, which is similar to what our standard
microATX test system puts out while sitting idle in the open. This is great
for those concerned about noise but a faster fan would appeal to more users,
especially as it’s the sole case fan. The low setting is basically useless as
the fan runs too slow to move much air. Any reasonably powerful fan-cooled video
card will likely drown out the high setting during load.

Not only is the stock fan quiet, it has a very nice sound as well. On low speed,
its acoustics are completely benign with a primarily broadband profile. On high
speed, it develops a moderate hum and slight clicking audible up close but it
is still generally quite smooth.


System Measurements (HDD on bottom)
System State
CPU + GPU Load
System Fan Speed
Low / 560 RPM
High / 1100 RPM
GPU Fan Speed*
1770 RPM
2350 RPM
1900 RPM
CPU Temp
HD Temp
GPU Temp
21~22 dBA
27 dBA
24 dBA
System Power (AC)
*set as low as possible to maintain a GPU temperature of ~90°C on load.
CPU fan at 9V.
Ambient temperature: 22°C.

While we were concerned about the effect of impeding the airflow with a bottom-mounted
hard drive, our test results were surprisingly good. Sitting idle with the exhaust
fan set to low, everything ran cool and machine was relatively quiet. The CPU
stayed closed to the 30°C mark and the GPU didn’t exceed 40°C, while
the total noise output was 21~22 dBA@1m. On full load, the CPU temperature rose
to 75°C and a GPU fan sped up to 2350 RPM to keep the GPU at ~90°C;
in this state the machine was 4~5 dB louder. Switching the exhaust fan to full
speed helped considerably, cooling the CPU and hard drive by an additional 4°C
and 3°C, respectively, and allowing the VGA fan to be slowed by a significant
450 RPM. This cut the noise level substantially to just 24 dBA@1m, not much
louder than idle state.

The combined noise of the stock fan and components was generally pleasant when
the system was idle, though at closer proximity, the growly tendency of the
HD 6850’s small fan was more clearly audible. At distance, the sound was soft
and gentle with just a hint of a hum, without noticeable hard drive vibration.

System Measurements (HDD on side)
System State
CPU + GPU Load
System Fan Speed
Low / 560 RPM
High / 1100 RPM
1770 RPM
1470 RPM
CPU Temp
HD Temp
GPU Temp
21 dBA
24~25 dBA
24 dBA
System Power (AC)
*set as low as possible to maintain a GPU temperature of ~90°C on load.
CPU fan at 9V.
Ambient temperature: 22°C.

For our second test configuration, we moved the hard drive to the side and
rotated the CPU cooler (to avoid interfering with the drive bracket). In idle,
there wasn’t much change, aside from a slightly hotter CPU and hard drive, but
on load, things got interesting. Removing the hard drive from the floor opened
up a lot of airflow and gave the graphics card much needed breathing room. The
GPU temperature was well under 90°C even with the GPU fan at minimal speed
(note: a quirk of the card’s fan control system allows it to run
slower on load than idle). However, turning the CPU heatsink made it less effective
and its new orientation caused the fan to suck up hot air coming off the graphics
card and blow it directly into the power supply above. So while the GPU fan
speed was lower than when the system was idle, the power supply fan went into
overdrive, bringing up the overall noise level with it. The hard drive also
ran hotter due to its higher position in the case, lack of ventilation, and
proximity to the video card. Speeding up the exhaust fan had a much smaller
impact than the first configuration, though the net effect was positive for
both heat and noise.

The overall noise level was similar to the first configuration, but side
hard drive mounting made its vibrations audible. Compared to bottom hard drive
mounting, the 90 Hz peak created by the motor’s 5400 RPM speed rose by more
than 10 dB, imbuing the system with a noticeable hum. The acoustic profile
wasn’t that different but it was more audible than the first configuration.

MicroATX Case Comparison (Load)
Fractal Design Define Mini
SilverStone Sugo SG09
Rosewill Legacy U3
SilverStone Temjin TJ08-E
Size (liters)
System Fans
2 x 9V
2 x 5V, 1 x 9V
1 on high
1 x 10V/low
GPU Fan*
1670 RPM
1680 RPM
1900 RPM
2330 RPM
CPU Temp
HD Temp
GPU Temp
22~23 dBA
24 dBA
24 dBA
24~25 dBA
System Power (AC)
*set as low as possible to maintain a GPU temperature
of ~90°C.
CPU fan at 9V.
Ambient temperature: 22°C.

With the hard drive mounted on the bottom, the Legacy U3’s thermal and acoustic properties were similar to that of another compact microATX case, the SilverStone Sugo SG09.

MicroATX Case Comparison (Load)
CPU Temp
GPU Temp
Fractal Design Arc Mini R2
(fans at 5V)
21~22 dBA
Fractal Design Define Mini
(fans at 9V)
22~23 dBA
SilverStone Temjin TJ08-E
(fan on low/10V)
24~25 dBA
SilverStone Sugo SG09
(2 fans at 5V, 1 fan at 9V)
24 dBA
Rosewill Legacy U3
(bottom HDD, fan on high)
24 dBA
Rosewill Legacy U3
(side HDD, fan on high)
24 dBA
Lian Li PC-V354*
(fans at 9V)
26 dBA
SilverStone Precision PS07
(fans at 9V)
25 dBA
*Results using Noctua NH-C12P instead of NH-U12P due to compatibility issues.

When we boil down our microATX case test data to just the most
important aspects (CPU and GPU temperature, overall noise), Fractal Design’s
Arc Mini R2
and Define Mini towers
remain the top performers, followed by SilverStone
Temjin TJ08-E
. The Legacy U3 performance is average but it’s an impressive
showing by the smallest case with the least amount of forced cooling (just one
120 mm fan).


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.


Rosewill has produced an attractive microATX case. The Legacy U3’s aluminum
composition and solid top and front faces gives it a touch of luxury lacking
in most competing models. We generally don’t favor side windows, but the U3’s
window has a pleasant look due to its large size, shape, and near-symmetrical
placement on the panel. The interior design does well to compensate for the
lack of direct intake airflow, allowing it to achieve effective and efficient
performance relative to its 20 liter volume. There are several microATX cases
that can deliver better thermals and acoustics but none come close to the U3’s
size; the case is closer in volume to a medium-sized mini-ITX case than a typical
microATX tower. The stock fan has an innocuous sound and is very quiet, so quiet
that the included fan controller isn’t necessary for all but the quietest of

What the U3 lacks is flexibility, primarily due to its very size. Drive support
is restricted and the options it offers for 3.5 inch hard drives have downsides.
The bottom position blocks a significant amount of ventilation for the graphics
card, while the side bracket is susceptible to hard drive vibration and interferes
with large side-blowing tower heatsinks. Choosing between the two may boil down
to which components can better handle extra thermal stress, the GPU or the CPU/PSU.
Longer graphics cards are not supported and even cards in the 9.5~10 inch range
are a tight fit due to case geometry.

The Rosewill Legacy U3 currently sells for US$90, which is pretty good
considering its all-aluminum construction. It’s perfect for DIYers looking for
a microATX solution with a small footprint, so long as you understand its limitations.
It’s not well-suited for high-end configurations or tons of storage, but with
modest components and proper planning, a relatively cool and quiet experience
is easily attained despite its size.

Our thanks to Rosewill
for the Legacy U3-B case sample.

* * *

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* * *

this article in the SPCR Forums.

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