The versatility of the compact power units
is flooding: SFX12V (in several different implementations), TFX12V, CFX12V,
LFX12V, FlexATX... So, we will discuss the units from two very popular
categories: TFX12V units are commonly used in compact system cases, while
FlexATX power units are also a popular choice for U1 servers.
There are a whole lot of different types of
compact power supplies: SFX12V (in multiple versions varying in size and layout
part), TFX12V, CFX12V, LFX12V, FlexATX ... It's almost impossible to collect
them all in one review and it's almost unnecessary because they are not
interchangeable, so our tests will be concerned with only two varieties TFX12V
PSU is a popular choice for compact computer while FlexATX PSU can be found in
the 1U server, next to desktop PCs.
It must be noted that the PSUs we're going
to test can not be compared directly. Seasonic's products are newer and
certified for the 80 PLUS Gold standard whereas the Enhance ones are older and
only comply with the 80 PLUS Bronze standard or even the basic 80 PLUS
standard.
Anyway, we are often faced with the same
form factor, but it is really important when considering the rising number of
compact computers. That's why the difference in class doesn't prevent us from
discussing them in a single evaluation.
Testing methodology
The following article provides detailed
description of our test methods and equipments and a brief explanation of what
the specified and tested parameters of power supplies mean: X-bit Labs
Presents: Power Supply Units Testing Methodology. If you feel overwhelmed with
the numbers and concepts abound in this review, see Methodology.
You can also visit the Cases / PSU to check
our evaluation of other PSU models we've tested in the laboratory.
We will mark the power consumption of three
system configurations (discussed in our article "PC Power Consumption:
How Many Watts Do We Need?”) in the cross-load diagrams. This will help you
discover whether the tested PSU can meet the requirements of a real-life PC.
Testing participants
Seasonic SS-300M1U and SS-350M1U
These PSUs are designed for 1U mini server
as indicated by the model name. However, they are also compatible with FlexATX
(namely, Low-profile Power Supply # 2).
Recalling compact computer system cases we
tested, the Cooler Master Elite 100 won't accommodate a PSU of that length (the
HDD rack will get in the way): a shorter PSU is required, even though the
mounting holes coincide. Such short PSUs are available too, though they are not
described in the specifications of FlexATX. Indeed, Seasonic markets its
shorter model (with 150 mm in length) as FlexATX whereas its 190mm PSU is
positioned as ATX12V v2.31/EPS12V.
There are computer cases as Delux DLC-MS126
which comes with 190mm PSU. Therefore, one of these Seasonic models can be used
to replace the Delux’s bundled PSU (which is reported to be very noisy).
These PSU, as the other products mentioned
in this article, come to us without any packaging, so we will not be able to
describe their accessories. Go straight to the PSUs themselves.
The exterior design
The
exterior design
It is difficult to make anything
extraordinary in terms of exterior design when it comes to this form-factor.
The back of the PSU can only differences from the same-class products in the
shape of the punched-out grid over the 40mm fan.
The
other end of the case is somewhat more original.
The other end of the case is somewhat more
original. Power cable can be removed, which is unusual for this form-factor (we
will discuss the cable system in more detail soon). There are square vents at
the bottom and two rows of oval ones in the top panel of the case.
Circuit design
Circuit
design
The 300 and 350W models are expectedly very
much alike in their interior design.
They
vary in electrolytic capacitors
They differ in electrolytic capacitors
installed at the output. The low-profile model has electrolytic capacitors from
United Chemi-Con and Rubycon.
Rubycon
capacitor
The higher-wattage model only has Rubycon
capacitors (at least where we can read their mark).
The
component density is very high
The component density is very high, as you
might expect from a compact PSU that is supposed to supply 300-350 W of power,
so we can't examine the components easily.
These
PSUs feature dedicated voltage regulation
Anyway, we can see that these PSUs feature
dedicated voltage regulation, the card with small DC-DC converter chokes being
located above the output capacitors.
There’s
a large daughter card that goes along the side of the case
There’s a large daughter card that goes
along the side of the case and is connected to the above mentioned voltage
regulator card with a cable.
Infineon
ICE2QR4765 Chipset
The standby source is based on an Infineon
ICE2QR4765 chip which is used in the lastest full size ATX PSU from Seasonic.
The
mains connector and filtering circuitry
The mains connector and filtering circuitry
are shown as typical Seasonic PSUs.
Cable and connectors
The Seasonic SS-300M1U and SS-350M1U PSUs
are equipped with the same selection of cables and connectors:
·
One mainboard cable with a 20+4-pin connector
(33 cm)
·
One CPU cable with a 4-pin connector (34 cm)
·
One cable with two PATA power connectors and a
floppy-drive plug (35+15+15 cm)
·
Two cables with two SATA power connectors on
each (29+15 cm)
The cable system
of these PSUs is quite original:
The
cable system of these PSUs is quite original
The entire bundle of cables is connected to
the PSU with two connectors, as you can see. For desktop applications, 350W
model will benefit from a dedicated connection to the graphics card if it was
to be used in a computer game.
Specifications
·
Total power: 300W/350W
·
Input: Full Range
·
Input frequency: 47/63
Hz
·
The launch, cold start:
100A maximum
·
Efficiency: >87%
·
Ripple/ Noise: >1%
·
MTBF, full load at 25A amb. (not include DC
fan): >100K hours
·
Power Factor Correction:
Active PFC, 99% typical
·
Safety: CUL, TUV, CB
·
EMC: CE, FCC, C-tick
·
Output: +3.3V @ 12A, +5V
@ 16A, +12V @ 29A, -12V @ 0.3A, +5Vsb @ 2A
·
Connectors: Cable custom
module
·
Dimensions (WxLxH):
3.2x7.5x1.6 inches / 81.5x190.0x40.5 mm
The Seasonic
SS-300M1U and SS-350M1U have similar specifications except for the overall
wattage and a slight difference in the load capacity of their +3.3V and +5V
rails. They can deliver nearly all of their output power through the +12 V rali
while the load capacity of the other rails are quite low (70-80W, more than
enough for a modern computer)
These PSUs comply with the 80 PLUS Gold
efficiency standard.
