No-name brand PSUs vs Known Brands: MAD testing

Cases & PSU/Power Supplies by jmke @ 2008-11-28

We were invited to visit Cooler Master´s brand new power supply testing setup, a very high end installation build to deliver up to 1200W and higher load to any PSU hooked up to the system. We bought some cheap PSU units from local Belgium stores to see how they would measure up when stressed to their rated wattage... read on to find out about the carnage.

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Finding Sweex\' sweet spot

Sweex Low Noise 650W

Sweex makes a multitude of products, ranging from KVM switches, LAN cables, mice, routers, webcams, and also power supplies, we got their highest end 650W Low Noise unit for €49 at Alternate.

Sweex ( manufactures computer-related products and has grown into a leading, mature player in the European market for consumer IT. From its head office in Delft (the Netherlands) and the nearby logistical centre in Hook of Holland, an intricate distribution network attends to Sweex partners in 45 countries in Europe, the Middle East and Northern Africa. The Sweex office in Taipei (Taiwan) guarantees the best possible time to market for each product. The 50 Sweex employees possess clear-cut ‘can-do’ mentalities, with teamwork being one of the major pillars for the company’s success.

Madshrimps (c)

In the looks department the Sweex doesn’t disappoint, it has a nice finishing and a hidden fan inside, there are also enough connectors to power modern day AMD/Intel systems.

Looking closer at the specifications label we can see that this unit has 2 12v rails;

  • 3.3v: 32A
  • 5v: 30A
  • +12v1: 17A
  • +12v2: 16A
  • -12v : 0.3A
  • +5 VSB : 2A

    Madshrimps (c)

    Promising numbers here, so let’s start the first test, loading the PSU close to 50% of rated capacity:

    Madshrimps (c)

    At half load the Sweex delivers close to 80% efficiency, the volt lines remain stable with minimal fluctuation. Power factor however is noticeably low at 0.51 (51%)

    Let’s try with a slightly higher load, closing in on 75% of rated capacity

    Madshrimps (c)

    Efficiency remains high, this unit is very close to a 80Plus rating indeed. Again voltage rails are well within ATX specs.

    Let us try for 100%? We started increasing the load to obtain that goal the PSU wouldn't take it, here's the maximum it would do:

    Madshrimps (c)

    This was the highest we could get before the PSU would auto-shutdown due to overload, it does reach 663W at the wall outlet, but with lower efficiency at 76% the output is a far cry from the rated 650W. Voltage lines remain stable though throughout the test.

    Madshrimps (c)

    Overall the Sweex was not half bad for the price; it did not break down when overloaded, got stable voltage rails, better than expected efficiency. It doesn’t deliver the rated wattage though which makes this unit incorrectly advertised for sure.

    So how exactly did we test these power supplies? Geoffrey our local PSU guru will go into that on the next page ->
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    Comment from thorgal @ 2008/11/28
    Great article and a big thank you to Coolermaster !
    Comment from Rutar @ 2008/11/28
    indeed a great article