230VAC Efficiency, Power loss, PFC

With higher input voltage is the efficiency increases as well. We have measured a very nice 83.33% efficiency at just 40% load. In total we had more than 80% efficiency from 20 to 90% load which is a very good result from the OP650. This power supply will always provide good results in PCs with more than 130 watts constant load when connected to 230VAC power.



The loss of power is not that large as a result of the high efficiency at 230VAC. The upper line marks the power input and the lower line marks the output. The space in between is the power which has been lost during the work.



Again, we tested the standby power draw of the Silverstone supply, this time with 230VAC. With 230VAC the OP650 is using 1.7 watts of energy while doing "nothing" which is a slightly higher result than what we saw when connected to a 115VAC power grid. If you leave the PC off for a longer time you should always hit the switch or even unplug the cable. This not only saves you money, but could potentially help save wear and tear due to power surges, especially in areas with unreliable power.

The standby-efficiency was again tested with the loads of 0.1, 0.5 and 3.0 Ampere on the 5VSB rail while the power supply is not running. We see that the efficiency is slightly lower with 230VAC than with 115VAC. At 3 Ampere loading it is the same like with 115VAC.


The power factor correction with 230VAC was at an average level and working fine.



230VAC 12V Rail Tests Temperatures
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  • Araemo - Friday, July 13, 2007 - link

    That makes sense, and makes me think my guess about the 20A limit is possibly a contributing factor - It would be a safety issue if someone hung 40A worth of fans, lights, motorized case windows, whatever you want.. off of one pair of wires (IE, one molex connector feeding into the mass of extenders and passthrough connectors that most fans and lights I've seen use.).

    You'd likely overheat the wires carrying all that power, if not the connectors as well, which could cause fire or electrocution hazards.

    While a GPU may draw significantly more than 20A, they are also using 3 pairs now, so the actual power draw will be closer to 20A per pair.
  • DerekWilson - Friday, July 13, 2007 - link

    The PCIe V2.0 PSUs I've seen suggest only using connectors from the same 12V rail for PCIe graphics cards -- because if you don't, you'll be connecting the common from two different 12V rails together.

    This can cause issues.

    If a graphics card has one 4pin and 1 8pin connector, like the HD 2900 XT, the GPU can potentially draw up to 225W from a single 12V rail through 2x PCIe graphics power connectors (3 pairs). That's about 19 amps through one rail for one PSU, but not over each pair.
  • SilthDraeth - Friday, July 13, 2007 - link

    They explained it.
    The Intel ATX standard calls for no more than 20 Amps per 12V rail. So in order to avoid maxing out a single 12V rail at 20 Amps, PSUs have multiple rails support up to 20 Amps each.

    If you use a single rail that can max out at 54 Amps as stated here, then you do not need the additional rails, but you are going against the ATX standard.
  • Duraz0rz - Friday, July 13, 2007 - link

    Also, I didn't see if there was a reason that it was advertised as a single rail, yet you have 4 12V rails.

    Nice article...really love the line curves for the load outputs. One thing I noticed missing is ripple testing. Any reason why it's not here?
  • SilthDraeth - Friday, July 13, 2007 - link

    That confused me as well. I think they mentioned that the PSU supposedly includes an ability to turn the other rails off, but it doesn't work, and it always has 4. They did state the PCB was originally designed for 4 rails.
  • Duraz0rz - Friday, July 13, 2007 - link

    Nevermind...disregard my statement about the ripple testing. I probably just missed it in the original article after skimming the comments from it :)

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