The heady days of racing
towards 1 Kilowatt power supplies left us with a nice gift - to achieve power
densities of 1Kw, 1.2Kw or even 1.5Kw required manufacturers to use better
electrical components, develop more efficient circuit designs and devise
quieter cooling options. The technological expertise gained from developing those +1Kw
enthusiast grade power supplies eventually trickled down to the everyday power
supplies we all rely on now.
themselves have also had a hand in shaping modern power supplies, ideas
that began as mods talked
about on forums include modular sleeved cables, duty reactive fans, matt black PSU chassis and even fan-free thermal solutions.
In this article PCSTATS will examine a 760W power
supply from Seasonic's flagship
modular gaming "X" series. The Seasonic SS-760KM is an Active Power Factor
Correction (A-PFC F3) power supply that boasts an80 Plus Gold rating. It features a +12V rail capable of delivering 63 Amps, four 6/8 PCI Express videocard power
connectors and the convenience of modular cables. The Seasonic SS-760KM X-760
power supply retails for $180CDN
($180 USD, £90 GBP) at Canadacomputers.com and is covered by a five-year warranty.
Under the matt-black steel case and honeycomb air vents are a few
clever electrical choices. Seasonic use solid state aluminum polymer capacitors
strategically throughout, for greater heat tolerance Japanese 105°C rated
caps, to reduce current transmission resistance gold plated terminals. Furthermore,
where the modular cables connect to the X-760, Seasonic employ
a DC-to-DC converter board rather than a bundle of wires soldered
to the modular cable jacks. Seasonic insist that by moving the +3.3V
and +5V voltage regulator modules to the connector panel it has minimized
voltage drops and impedance, improved airflow by doing away with unnecessary
wires within the PSU and aided heat dissipation with a simple, unobstructed
Active cooling is provided by a single 120mm Sanyo Denki 'SanAce 120' fan (model: 9S1212F404) that remains off until PSU
load demands active cooling. This three phase fan approach is called 'Hybrid
Silent Fan Control'. I have to admit that is a bit startling to see the fan
stationary while the power supply is powered up... the manufacturer
attaches an extra warning label to inform
consumers. When the PSU
temperature sensor hits 25C the fan spins at ~1000RPM (16 dBA) and beyond that moves to
full speed (2200RPM) when PSU load moves past 50%. Sanyo Denki fans
are Japanese made, balanced to eliminate vibrations and use ball bearings which are less likely to dry out and
The modular cabling of the Seasonic X-760 makes it easy to access components,
letting you build a cleaner PC that's less cluttered so airflow is improved all
around. As a modular power supply, Seasonic's X-760 is loaded with all the cables
necessary to hook it up a multi-videocard equipped system. It ships with four
PCI Express power connectors, all of which are convertible 6/8-pin cables.
There are eight 4-pin molex connectors, eight SATA connectors and two FDD 4-pin
connectors for hard drives/floppy disks and other peripherals. Rounding out the package is one 8-pin EPS12V
cables, one 8/4-pin EPS12V/ATX12V auxiliary cable and a 24/20 pin convertible ATX main power cable.
Seasonic's X-760 power supply is compatible with ATX 2.2 spec standard and
supports the 24 pin ATX power connector by default. Seasonic rates the the +3.3V
and +5V rails at 25 Amps each, for a total combined output of 125W. There is a
single +12V rail that can output 63 Amps/756W.
PCSTATS is often asked what 80 Plus certification means in the real sense.
Quite simply, a power supply draws a certain amount of overhead itself to
convert 120V AC to a certain amount of DC power. As an example, for a 120W load
the Seasonic X-760 should theoretically be 87% efficient and thus draw no more
than about 138W in total to get the job done. In other words, an 87% efficient
power supply will waste 18W to supply 120W, so the total power draw is thus 18W
+ 120W = 138W.
By comparison a 60%
efficient PSU would theoretically draw 200W to supply a 120W load, with a whopping 80W
wasted as heat energy. Both the heat and excess power consumption can add up
The Seasonic X-760 measures 160x150x86mm in size so it will fit into any ATX desktop case. It
comes in an easy to grip matte black finish with gold accents that
will look sharp if your computer tower has a window. It is
fully 120V/240VAC compliant, 50/60Hz, so it may be used anywhere in the world.
The unit is also impressively hefty, a testament to Seasonic's build quality and choice of high quality materials.
Let's quickly get familiar with the outside of the Seasonic X-760 before disassembling it for a
closer look at the internal components.