SilenX 14 dBA 400W PSU

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May 4, 2003 -- by Mike Chin

Product SilenX 14 dBA 400W PSU
Manufacturer Exotic PC / Fortron-Source
Supplier Exotic PC
MSP US$110

The SilenX 14 dBA power supply was one of the most celebrated products discussed in the forums of Silent PC Review. The posts about the SilenX PSU seemed to begin around February, and quickly became a series of big raves by numerous forum members. The general consensus in the SPCR forums that it is the quietest fan-cooled PSU available. Naturally, the SilenX PSUs quickly got short-listed to be reviewed in SPCR.

ExoticPC sent a sample at the beginning of March. The original intent was to have the review published by around the end of March, but then confusion about the SilenX brand began.

Peter Kim, who was originally employed by ExoticPC, broke away to begin his own independent business under the name of The PSUs sold at are branded SilenX. At the same time, ExoticPC continues to sell SilenX brand PSUs as well.

Without getting into the details, suffice it to say that the SilenX brand PSU supplied by and appear to be essentially identical, notwithstanding changes made by either or since mid-March. Regardless, please note that this review refers specifically to the SilenX 14 dBA 400W PSU sold by ExoticPC. As far as I am aware, ExoticPC have not made any changes in production since then.


The reason Fortron-Source is listed alongside ExoticPC under manufacturer at the top of this page is because they are the OEM supplier. Like several other 300W quiet PSUs reviewed by SPCR, the SilenX 400W is based on a Fortron-Source. On the outside, except for the big ExoticPC SilenX label, this PSU looks identical to a Fortron-Source FSP400-60PFN.

One distinct difference between this PSU and the 300W models by Nexus, Verax and Zalman is that the intake vents are only on the side opposite the fan. The other PSUs mentioned have vents on the "bottom" or cover as well. (See this Nexus example.) Airflow behaves very similar to liquid flow in that it takes the shortest path. Having the intake vents only on the back panel means the air is forced to travel the entire length of the heatsinks in the PSU before it is blown out. This strikes me as better for cooling.

The absence of a manual voltage switch (120/240VAC) indicates that the PSU has Active PFC, which is generally a good thing for electrical efficiency.

The fan visible behind the wire grill is labeled Ahanix, which happens to be the parent company of ExoticPC. The model info is: 825 - 15 - 20; 12V - 0.07A - 0.84W.

The label also identifies Kaimei as the fan maker. It so happens that Kaimei is the original name of a Taiwanese company called Jamicon, who make fans, capacitors and ballast. The closest fan match is JF0825X1E, rated at 19 CFM, 1500 RPM, and 15.9 dBA. This noise rating is the lowest for any fan I've had the opportunity to examine.


These photos of what lies under the hood are revealing.

Quite simply, they are the largest, heaviest heatsinks I've encountered yet in a fan-cooled PSU. I do not have a scale to measure the mass accurately, but it is definitely heavier than the 300W PSUs mentioned above. I thought initially that these heatsinks were installed especially for the SilenX PSU by Fortron-Source, but later discovered that Fortron's own 400W ActivePFC model has the same heatsinks.


  • 14 dB(A) claimed; not clear whether at minumum, typical or maximum power.
  • Output over voltage protection
  • Short circuit protection on all output
  • Reset Table power shut down
  • Approved by:Approved by UL 1950, CSA C22.2 No. 234 Level 3, IEC 950, TUV EN 60950 or VDE 0805, NEMKO EN60950
  • 100% burn-in under high ambient temperature (50C)
  • Vacuum-impregnated transformer
  • MTBF: >50K hours at 25C
  • 100% Hi-pot & ATF tested
  • Line input fuse protection


  • Remote ON/OFF Control
  • Active PFC
  • Temperature range:
    • operating 0C~40C
    • storage -20C~+65C
  • Temperature coefficient: 0.01% / C
  • Transient response: output voltage recovers in less than 1ms max. following a 25% load change
  • Dielectric withstand: input to frame ground 1800 for 1 second
  • Humidity: 5~95% RH
  • Efficiency: 65% at DC24 Input, at full load
  • Power good signal: turn-on delay 100ms to 500ms, off delay 1mS min.
  • Overload protection: 150% max.
  • Inrush current: 60A cold, 80A warm at 264 VAC


AC Input
95~264 VAC, 47~64 Hz
DC Output
Load Regulation
Ripple + Noise
50mV P-P
50mV P-P
120mV P-P
120mV P-P
100mV P-P
50mV P-P
Min Current
Max Current
Max Power
Max Power


There are a total of 7 wire sets:

  • 3 cables, 16" long, each with a single 4-pin IDE drive connector
  • 1 cable, 20" long, with one 4-pin IDE drive connector and one floppy drive power connector
  • 1 cable, 20" long, with two 4-pin IDE drive connectors
  • 20" long cable for main 20-pin ATX connector
  • 20" long cable for dual 12V (P4) connector
  • 3.3V connector on another 20" wire set.

It's noteworthy that 3 of the cables terminate only in one 4-pin connector each. Is that waste or high electrical isolation? Also, none of the cables are very long (generally a good thing for standardard-size PCs), and all are close to the same length.

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