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Fortron/FSP Zen 400 (Continued)

Silent PSUs: Fortron Versus Silverstone
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On the rear of the power supply you’ll find the IEC socket and a blue illuminated main switch. The latter is of particular importance, as a user operating a passive power supply cannot hear whether or not it is switched on. There are no other indicators showing the operational status of the unit.

The power supply is a full range unit that can be operated on a voltage ranging between 110 V and 240 V. There is no need to manually switch between the voltage ranges.

The output of the power supply is 400 watts, and 560 watt peaks are possible for short periods of time. The combined performance of the 3.3 V and 5 V rails is a maximum of 130 watts.

During use, the power supply makes its presence known by a high-pitched, high-frequency noise that occurs most often when under heavy use. Up to a load of approximately 250 watts this noise can hardly be heard, but the higher the load gets, the louder the noise. This is a very annoying noise that detracts from the "silent PC" concept.

With no additional ventilation, constant operation under full load at 400 watts is not possible. The power supply switches itself off due to overheating after approximately two hours. A level of 300 watts, however, can be maintained permanently. A minimal movement of air in the computer case—such as a slowly rotating 120 mm fan—enables the device to be operated permanently at high load.

The test with the D201GLY2 board from Intel was not a problem—this kind of mini ITX board often causes problems with power supplies.

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  • 1 Hide
    knowom , August 20, 2008 1:22 PM
    I think they'd be great for a digital audio workstation environment now if only there was some more competition in this market segment to drive prices down to a more decent level.
  • 0 Hide
    mdmadph , August 20, 2008 2:42 PM
    "The +12V CPU connection is only available as 4-pin version, which can lead to problems with some boards that require an 8-pin connection."

    Know of many HTPC boards that need an 8-pin CPU connection? :\ I sure don't.
  • 0 Hide
    one-shot , August 20, 2008 3:48 PM
    ^^lol
  • 1 Hide
    Anonymous , August 20, 2008 3:51 PM
    I have read 3-4 other reviews of the zen 400W, and I'm pretty sure there has been no mention of the high pitched sound. It's not a good sign for the zen, but it's probably a faulty powersupply tested in this review.
  • 1 Hide
    gwolfman , August 20, 2008 4:19 PM
    Ummmm, so where's the temps? The review is practically pointless without temp measurements on a fanless PSU. BOOOOO!
  • 0 Hide
    jeffunit , August 20, 2008 5:18 PM
    Without specifying the input voltage, efficiency measurements are pretty useless. Running at 240v will yield a few percent higher efficiency than 120. Even 240v will be more efficient than 220v.
  • 6 Hide
    kittle , August 20, 2008 6:25 PM
    Re-run your review and include tempratures. Its pointless w/o them.

    If you have found a fanless PSU thats safe to touch -- thats great. but if these things get to 40, 50, 60c - then we need to know not to buy them.
  • 0 Hide
    Anonymous , August 20, 2008 10:40 PM
    I own the Zen400 power supply and it's exactly what I needed for a quiet HTPC, to the point where it's literally impossible to tell when the PC is on. During normal operation I have never heard the high pitched sound this review mentions (although it did output a sound similar in volume and annoyance to a smoke alarm when I failed to plug in the power cable to the graphics card - it was clearly an error/failure tone).
  • 0 Hide
    Anonymous , August 20, 2008 11:42 PM
    In regards to the lack of the 8 pin CPU 12v connector, if you can find a motherboard of which the 4 +12v pins of the port are not electrically connected, please point it out to actually justify needing the 8 pin connector. To be honest, a motherboard with a single +12v pin isolated to only 1 or 2 vcore phases would'nt be any motherboard you would want to purchase, for power efficiency reasons.
  • 0 Hide
    Alternator , August 21, 2008 1:12 AM
    I agree with the above posters, temps would be nice, and not just of the PSU...

    I am quite interested in getting a capable (above 400watt) PSU that doesn't require a fan, but I really need to keep an eye on the temperatures.

    I have a fanless mb and vid card (3850 radeon), and would wonder if adding a fanless psu into the mix would jeopardise the system by reducing the air flow through the case. (after all I wouldn't get a fanless PSU if my other components were noisy to begin with!?)

    Perhaps an article focused more on configuring a quiet computer (for the purpose of gaming) could be in order?
  • 0 Hide
    fadirocks , August 21, 2008 1:43 AM
    knowomI think they'd be great for a digital audio workstation environment now if only there was some more competition in this market segment to drive prices down to a more decent level.


    this is not true you shouldn't have any equipment in recording area except for microphones and the band, so the recording occurs next door on whatever medium you use. also if you want to have silent recording station then it's probably cheaper just getting a silent laptop which will have enough power to record multiple channels easily

    it's nice to have a silent PSU but at this price and low wattage eeek
  • 0 Hide
    knowom , August 21, 2008 3:15 AM
    fadirocksthis is not true you shouldn't have any equipment in recording area except for microphones and the band, so the recording occurs next door on whatever medium you use. also if you want to have silent recording station then it's probably cheaper just getting a silent laptop which will have enough power to record multiple channels easily it's nice to have a silent PSU but at this price and low wattage eeek


    Not everyone has the luxury of spare room to store noisy recording equipment in and reason for storing it in another room is due to noise so how is that not true? Yeah you'd need fan less psu, cpu, and video card plus a SSD or two ideally as well, but if you were getting a fan less psu chances are you'd want the other things as well anyway.
  • 0 Hide
    Anonymous , August 21, 2008 9:14 AM
    I have a fanless CoolMax 400w (discontinued). This runs my gaming rig believe it or not. Core 2 Duo, HD4850, 2 drives in RAID 0. It's not the fastest thing on the planet, but it can run most games at 1920x1200 without breaking a sweat. My question is: who needs 1200w? ;) 
  • 0 Hide
    Anonymous , August 21, 2008 9:18 AM
    My quiet PC (so quiet I can barely hear the difference between on or off) can be found here: http://quietpc.rosboch.net

    I use 120mm fans from Scythe, a Scythe CPU heatsink, a Thermalright GPU heatsink with a 92mm SilenX fan and a fanless PSU. The hard drives are in Logisys drive silencers. All fans are controlled by a manual Zalman fan controller (you certainly don't want to run them at max). Case rattle has been eliminated with a judicious application of duct tape.

    Even though it is basically completely silent, the machine is certainly no slouch.
  • 0 Hide
    ize , August 21, 2008 5:57 PM
    kittleRe-run your review and include tempratures. Its pointless w/o them.If you have found a fanless PSU thats safe to touch -- thats great. but if these things get to 40, 50, 60c - then we need to know not to buy them.


    They claimed that the PSU had to shut down due to overheat. That never happens when it is touchable temperature so under full load it is a paws off.

    Also the efficiency numbers should give a fair indication what the temperature will be considering the loss becomes heat. I wouldn't go so far to say it is a pointless review. Its easy to tell from the info they give whether its too warm or not. Its just to read between the lines.
  • 0 Hide
    Anonymous , August 22, 2008 8:32 PM
    I have a ZEN and have never ever experienced the high pitched noise you describe. Mine is and has always been completely silent.
  • 0 Hide
    doomsdaydave11 , August 31, 2008 4:06 AM
    mdmadph"The +12V CPU connection is only available as 4-pin version, which can lead to problems with some boards that require an 8-pin connection."Know of many HTPC boards that need an 8-pin CPU connection? :\ I sure don't.

    It's for them SLI HTPC's. Don't you know??? :D 
  • 0 Hide
    evert , September 11, 2008 8:39 PM
    Hmm, and I guess a PSU like this would not be all that good for, for example, the Antec Mini P180 cabinet, with its separated compartment for the PSU which seems to rely solely on the fan of the PSU for air flow...
  • 0 Hide
    Anonymous , December 18, 2008 5:10 PM
    It's really strange that the editors chose Silverstone as their favourite in this countdown. You can all clearly see that in all tests, Fortron surpassed by far Silverstone, especially in terms of efficiency. What's going on here? Am I missing something?
  • 0 Hide
    tapher , April 24, 2009 6:46 PM
    Fortron's dual +12V combined cannot match the 32 A rating of the Silverstone single +12V at US wall voltage. This may be a considerable distinction between the two if one is looking to use a modern 2009 top-tier video card requiring more than the Fortron's tinier 27A combined.