Five 550 And 600 W 80 PLUS Platinum Power Supplies, Tested

Results: Rosewill Fortress 550

Efficiency According to the 80 PLUS Specification

Efficiency by Output Power

Our test suite doesn’t expose any significant differences between the Kingwin and Rosewill products. The efficiency values for both PSUs are really close when we perform our 80 PLUS Platinum compliance tests, and the two competing power supplies rightfully bear the coveted logo.

At low load, Rosewill's Fortress pulls ahead of the Kingwin supply by being one or two percentage points more efficient. At 25 W, the Fortress 550's efficiency is two percentage points above the Lazer Platinum 550 W's at 79 percent. Perhaps the fact that this power supply has no modular cabling helps. After all, each connector ever so slightly decreases efficiency.

When we measure the hold-up time, Rosewill's Fortress 550 achieves 17 ms, which is slightly less than the average of the other supplies, but still in compliance with the 16 ms demanded by the ATX specification. Like the other power supplies in this round-up, the Fortress passes our overload test, which subjects the power supply to 110% of its nominal load.

At the end of the suite, we check ripple and noise to determine the quality of the DC output voltage, generated from an intermediate AC voltage. The oscilloscope shows that the Rosewill Fortress sports significant ripples, which could be passable as long as they stay within the ATX spec. However, we measure a maximum of 170 mV on the +12 V rail, exceeding the ATX limit of 120 mV. Unfortunately, even the 149 mV average is too high.

A Closer Look at the PCB

The Fortress 550's main PCB is smaller than the one inside Kingwin's Lazer, most likely because Rosewill doesn't employ modular cables. Although both PSUs offer identical tech specs, their PCB layouts are not the same.

First, Rosewill’s input filter is located at the mains receptacle. This small PCB sports just two X and Y capacitors each, along with a choke coil. The rest of the input filter consists of two more X and two more Y capacitors, along with an MOV seated behind the bridge rectifier. The topology is LLC, and all components are sourced from Japan. The soldering quality looks OK, but it is by no means perfect.

  • what? no overload it until it blows test?

    and i was making popcorn.
  • mousseng
    Is that a typo in the first chart for Kingwin's Lazer? It claims that it fails 80 Plus's 50% load spec (82% of 92%); I assume that was meant to say 92% (since that's what the chart below it shows).

    Pleasant read, though, I like PSU reviews.
  • What happen to Seasonic? They have the 520W fanless SS-520FL Platinum version. No PSU test is complete without a seasonic to compare to, in my own opinion.
  • dudewitbow
    jupiter optimus maximusWhat happen to Seasonic? They have the 520W fanless SS-520FL Platinum version. No PSU test is complete without a seasonic to compare to, in my own opinion.they asked for vendors for the PSUs. Theres the offshoot chance that seasonic declined the offer. On other sites, the 520w fanless seasonic unit was compared to Rosewill's 500w silent night unit. The seasonic unit I believe in that review barely edged out a victory.
  • cangelini
    iknowhowtofixitEither the Rosewill FORTRESS was defective or your calibration was off for the last test. Your o-scope shots do not match those of other highly credible reviewers. Also, I'm curious of your testing methodology, but it was not listed.I believe this is still applicable to all of the power supply testing our German team does:,2657.html. I'm waiting for confirmation that I'm right.

    Edit: Yup, that's the correct testing equipment/procedure!
  • Dun dun dun..................... no acoustic performance measured, the only reason some people buy high end PSU's.
  • sebbesapa
    WOW! Thanks a bunch for including the 25watt "Low-Power PC" efficiency test! All other reviewers stop @ 20% load witch is not "idle" or "low load" at all. :-)
  • sanilmahambre
    Power supply unit is where a system builder cannot use a word "BUDGET"
  • jaideep1337
    I don't understand
    Why is the 80 plus spec officially test by having more load on the 3.3v and 5v rails?
    Clearly loading the 12v rail would give us a better overall image
  • jaquith
    Interesting, IMHO the most important aspect is 'Ripple Voltage' @ Rated Load. The only mention I see is a vague reference in your conclusion page.
    Never mind I see the ripple data buried in the individual tests. It would have been better in the summary side-by-side tests.

    Nice article.