Viewing page 3 of 5 pages. Previous 1 2 3 4 5 Next
INSIDE THE GREEN PS
The Green PSU is downright scrawny with its top off. No wonder FSP can claim
a 25% reduction in weight there's not much here! The internal components are both fewer and smaller
than in most other power supplies. The heatsinks are aluminum
plates wedged between the components, and the PCB doesn't occupy the whole space
inside the casing. There are fewer coils than usual, a single main capacitor,
and even the main transformer is about two thirds the "normal" size.
All in all, the Green PS is a little mysterious. How can a power supply this
"small" deliver 400W? How can it be cooled properly by the minuscule
(and extremely simple) heatsinks? Is smaller better?
Whatever the answer to these questions, FSP's engineers seem to have taken
an unusual approach to the Green PS. Intuitively, it is difficult
to believe that the unit can be cooled adequately, but if
it had a thermal problem, it would not have passed all of those safety certifications. Whatever the intentions behind the design, I
can't help rooting for the little guy.
It's pretty empty inside: Components are few and widely spaced.
What follows is an educated guess about how the internal cooling might work.
In comparison to most power supplies we've seen in the lab recently, component and heatsinks have been minimized, and there is a lot of
empty space. The lack of impedance should allow greater airflow through the PSU and perhaps cut down on "hot spots" where
there is little or no air movement to evacuate the heat. The shape and careful
positioning of the auxiliary exhaust vents seem to be designed to relieve back
pressure, and to ensure that there are no dead ends where the air has nowhere to
The empty space behind the rear grill means that some of
the air from the fan will exit without ever passing over the
heat-producing components. This is a short-circuit in the airflow,
but it may increase airspeed and minimize back pressure
in the rear half. The airflow in the front half will be
slower, since there is more impedance, but also higher pressure. It seems plausible
that the difference in pressure might be enough to cause a current from the
front to the back, thus drawing heat away from the components on the PCB.
This angle shows just how empty it is, about a quarter of the space is unused.
Only the engineers at FSP can confirm my guess about airflow design, but our
testing showed that the internal cooling is no worse (but no better) than most of the other power supplies
we've tested. Details of the thermal performance can be found on the next page, in
the test results.
Skinny, vertically aligned heatsinks offer minimal airflow impedance.
A medium speed, ball bearing fan from a manufacturer known for quiet fans.
The fan is from a manufacturer well known to SPCR: Yate
Loon Electronics. It's a medium speed ball bearing model with a rated
noise level of 34 dB (no A weighting or measurement distance listed). Yate Loon
has an excellent reputation for the low noise of their sleeve bearing fans, but their
ball bearing fans are less well known. Hopefully their ball bearing models are
as quiet and pleasant sounding.
CABLES AND CONNECTORS
There are a total of seven cable sets.
- 19" cable for main 20+4-pin ATX connector
- 20" auxiliary 4-pin 12V AUX connector
- 26" cable with two SATA drive connectors
- 2 x 26" cable with two 4-pin IDE drive connectors
- 32" cable with two 4-pin IDE drive connectors and one floppy connector
- 20" 6-pin auxiliary power connector for PCI Express
Plain vanilla cables: Not twisted or sleeved.
The Green PS has relatively few output cables, although there are easily enough
for most systems. The limiting factor is likely to be SATA connectors,
of which there are only two. There is a PCIe connector for a high power video card.
The wires themselves are insulated with an unfamiliar kind of plastic. This
is unusual, but not really surprising, since most wire insulation is manufactured
with lead. Naturally, the Green PS could not be environmentally friendly if
it used lead-based insulation... and it could not meet RoHS requirements either.
The wires are also of several different gauges. 18 gauge wire is almost standard,
but the Green PS used no less than three different gauges: Heavy 16 gauge for
the PCIe connector, 18 gauge for the +12V AUX connector and most of the wires
on the ATX header, and thinner 20 gauge for the IDE and SATA cables.
The rationale behind using different gauges of wire is to minimize voltage
drops for the longer cables that carry less current, while ensuring that the
highest powered cables don't melt under heavy load. It may also be used as a
cost saving measure, since thinner wires are generally a little cheaper.
|Help support this site, buy from one of our affiliate retailers!|