Silent Running: Two Fanless Power Supplies And A Quiet One, Tested

Measurements: be quiet! Straight Power E9 CM 480 W

Efficiency, According to the 80 PLUS Specification

Efficiency Across the Power Spectrum

In the test lab, the 480 W power supply follows and then surpasses the performance of the 580 W model. It conforms to the 80 PLUS spec even more closely, sporting particularly high efficiency at low loads. At 25 W, for example, the 480 W PSU comes close to 80% efficiency, which is a respectable number that ranks among the best performances we've seen. In standby, it only draws 0.18 W.

Our lab tests show that be quiet!'s E9 CM 480 W doesn't encounter any regulation issues, and also achieving low low ripple and noise values on the DC rails.

Last but not least, even when you're in a quiet room the Straight Power E9's fan can only really be heard close to the power supply itself.

A Peek at the PCB

The 480 W PSU's interior looks a lot like the 580 W model we've already reviewed. All be quiet! power supplies are manufactured by FSP and are similar to that company's Aurum family. Taiwanese firm CapXon makes the Straight Power E9's capacitors. Although they're not the premium caps from Japan, which FSP uses in its own-branded power supplies, they're still decent and shouldn't cause problems.

We did notice an extra ceramic capacitor in the mains-side circuit. Its task is to eliminate the chirping sound that sometimes emanates from power supplies. Another design feature intended to help reduce noise is a fan mount sitting on rubber grommets. This prevents vibrations from being amplified by the power supply enclosure. The manufacturing and soldering quality are both impeccable. Our only complaint is that FSP does not use heat shrink tubes to cover the locations where cables are soldered onto the PCB.

The be quiet! Straight Power E9 CM 480 W is very quiet and boasts an 80 PLUS Gold rating. It demonstrates no apparent weakness in our testing, and offers high efficiency across the entire load spectrum. Its feature set and quality are top notch, and although it is actively cooled, this power supply is the next best thing to fanless. Unfortunately, it isn't available to our U.S. audience, and only stands in as a comparison point for our other two passively-cooled contenders.

  • amuffin
    Seasonic, me gusta :)
  • zeratul600
    Why does americans are so picky about the noise rate??? i never stop to think about that! it has never become an obstacle to enjoy my pc experience
  • the1kingbob
    Fan noise has never bothered me much, which maybe why I own two 4870s... one of which has a jet plane I mean reference cooler on it..... sadly my wife doesn't care much for the noise, which lead me to buy her wireless headphones :)

    I think it is quite neat that they have fanless option. I would never take the risk, but if I did I would chose seasonic, my 750W has done me well.
  • s3anister
    zeratul600Why does americans are so picky about the noise rate??? i never stop to think about that! it has never become an obstacle to enjoy my pc experienceLast time I checked, Americans aren't the only ones who enjoy a silent computing experience...
  • amuffin
    zeratul600Why does americans are so picky about the noise rate??? i never stop to think about that! it has never become an obstacle to enjoy my pc experienceMany companies that are focused on silence such as Noctua and beQuiet! are not "American."
  • Deemo13
    I didn't know they made fanless power beans.
  • uruquiora
    Seasonic for the win :)
  • mesab66
    ZERTUL600......FOR THE VAST MAJORITY OF FOLKS, PERSISTANT/RELENTLESS NOISE QUICKLY BECOMES VERY ANNOYING!!..........give 100 folk a choice of 2 pc rooms - one near silent and one, noisy as hell. Riddle me many go for the quiet room?
    --> argument over.
  • mitko
    A year ago I built a water cooled system with an i7 2600k and 2 x Radeon 6990. The whole point of the water cooling was to make things extra quiet, which it did, except for the power supply. I tried two different Corsair AX1200 units before switching to a Nexus RX1100. The power supply is still BY FAR the noisiest component in the computer. Does anyone have a suggestion how to reduce the noise? I could not find any currently manufactured water cooled PSUs. Do you think it is possible to use 2 low-noise PSUs to power components on the same motherboard? Any other ideas are also welcome. I need at least a 1100W PSU, as I've actually measured the power consumption to be 1067W at 100% CPU and GPU load.

    For the record I am not an American and I don't live in the US :)
  • belardo
    In a quality modern PSU... can anyone really hear the PSUs?

    I've been buying Corsair and even $45 Thermaltake 500... and I cannot hear them... with the cover open. The problems with FANLESS PSUs and GPUs is that they become heat-sinks... sure they are quiet, but everything around them gets warm. You need to blow the hot air out.

    Going from a fanless GPU to something with a huge fan (H.I.S. brand) - the fans barely makes noise and use a rear exhaust and I can run the system fans at a lower speed.

    Mitko: get soundproofing material, apply to inside of case. Put case on floor.

    My case is on the desk, a foot or so away from me... its no louder than the A/C vent blowing air in the room.