I've got a sweex 650VA and the following hardware:

  • i7 3770k
  • 32 GB Ram
  • z77 Extreme 4
  • MSI nVidia GTX 980
  • 2 HDD 5.25
  • 3 SSD
  • 1 DVD RW

All supported by a 700 W power unit.

When I use particularly intensive games such as Metro Last Light Redux, after ~20 mins of gaming (cpu is used ~370% and videocard ~100%) the sweex ups starts beeping twice every 1 second (looking at the manual seems to indicate "overload").

What can I do to prevent/fix this problem?

How is this possible? An estimate of my system should be ~550W under extreme usage. Should I buy a new better ups? Should I set the spindle disks to shutdown on non usage? What do you think about the 700W power unit, is that enough?

Once I stopped the game, after ~1 min the beeping stopped.

I'm running Ubuntu 14.04 x64.

  • Is your monitor(s) and printer connected to the UPS as well?
    – LawrenceC
    Dec 26, 2014 at 12:56
  • No, my two displays are not connected to the ups, neither printer nor anything else.
    – Emanuele
    Dec 26, 2014 at 12:56
  • What is the brand and model of the power supply? Different units have different efficiencies, and the very cheapest ones might not have active power factor correction.
    – ntoskrnl
    Dec 26, 2014 at 19:22

1 Answer 1


The technical reference of the sweex 650VA says:

output power = 360W

The technical reference of the GTX 980 says:

Minimum System Power Requirement (W) = 500 W.

==> your UPS is most likely overloaded by the graphics adapter.

You can reduce the input by reducing the quality of the graphics. The settings are mostly called lower quality or higher speed.

  • Noooaaaa when I bought this I was told it's 650W... Ofc it doesn't work! Those ***** at Maplin lied to me...
    – Emanuele
    Dec 26, 2014 at 13:52
  • 9
    Volt-Amps (VA) and Watts (W) are not equivalent measures of power. Dec 26, 2014 at 16:44
  • 2
    The "minimum power supply requirements" published by graphics card manufacturers are wild overestimates for various reasons. The power consumption of @Emanuele's system is likely less than 300W on full load. However, the UPS is probably still not up to the task – when considering 80% power supply efficiency, 360W leaves 288W on the DC side.
    – ntoskrnl
    Dec 26, 2014 at 19:21
  • @Twisty I know, but I didn't check the label, and I asked specifically to have a UPS capable of supporting 500W... This is what I got sold... first (and last) time I trust them! Now I just bought a Trust Oxxtron 1500VA... this should be ok...
    – Emanuele
    Dec 26, 2014 at 20:06
  • Furthermore, the UPS outputs a "modified sine wave" (call it a near-square wave, it's more accurate) instead of a pure sine. The peak current on the rising edge is much higher, which might result in OCP protection kicking in sooner.
    – BjornR1989
    Dec 26, 2014 at 21:19

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