Rosewill Capstone-G1200 PSU Review

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Load Regulation, Hold-Up Time And Inrush Current

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

Hold-Up Time

Our hold-up time tests are described in detail here.

As we expected given the bulk capacitors' low capacity, measured hold-up time didn't meet the ATX specification's requirements. There simply wasn't enough space on the PCB for larger caps, which would have also had a negative impact on efficiency. The trade-off could have cost Rosewill its 80 PLUS Gold rating.

Inrush Current

For details on our inrush current testing, please click here.

This platform's small NTC thermistor results in higher inrush currents, taxing your home's electrical infrastructure.

Load Regulation And Efficiency Measurements

The first set of tests exposes the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 to 110 percent of the supply's maximum in increments of 10 percentage points.

We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.10A. This benchmark reveals whether a PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails. 

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Test12V5V3.3V5VSBPowerDC/AC (W)Efficiency%Fan Speed (RPM)Fan Noise dB(A)Temp In/Out(°C)PF/AC(V)

Our load regulation measurements show that Rosewill fails to match the competition. This doesn't surprise us, particularly when it comes to the +12V rail, because we haven't tested any ACRF topology-based PSU with great load regulation.

Under a 20 percent load, the PSU easily satisfies the 80 PLUS Gold efficiency requirement (87 percent). With a 50 percent load applied, the margin is a lot closer. But given our warm ambient test environment, we'll give the PSU a pass on this one. However, under a full load, the measured efficiency level was significantly lower than the permissible minimum. Obviously our 48°C operating temperature played a big part in this.

The big Capstone unit proved to be very noisy under tough conditions. During the first two tests, the fan rotated slowly. However, it sped up quickly, and with 70 percent load applied, acoustic output approached 52 dB(A). If you need a quiet PSU, avoid this one.

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • Giannis Karagiannis
    Quite low price for a 1200W unit but considering everything else I dont think its a good buy. Try better next time Rosewill...
  • Dark Lord of Tech
    Rosewill does have some Capstones that are great quality , The Super Flower models.
  • Dark Lord of Tech
    Also Enhance released a lot of nice V and VS series models for Cooler Master.
  • Aris_Mp
    Those older Capstones are EOL because they were older platforms which most likely aren't produced any more and on top of that Super Flower lately cannot meet demand, as the rumors say.
  • Dark Lord of Tech
    Super Flower is still pushing out a lot of units , I own 5 of he EVGA Super Flowers.

    The olser Capstones are solid , they are EOL , but were very good.
  • damric
    RIP Golden Green. You will be missed.
  • DSzymborski
    Really disappointing to see Rosewill slide back - those older Capstones made by Super Flower were really quite nice and you could frequently get excellent deals on them and I made a couple of builds for people with the semi-modular gold 750s. Too bad.
  • MasterMace
    It's too bad, the previous Capstones were so nice. This makes me wonder if they should have slapped a lower rating on this unit, instead of overshooting for a Gold 1200
  • firefoxx04
    I wish manufacturers didn't bother making crap power supplies for enthusiasts markets. The fact that they even sell is a huge problem.
  • Slobodan-888
    LOL, ripple is fine. It is within ATX specifications which states that is is allowed up to 120 mVpp RMS on 12 V rail.