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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  • Martimus - Friday, July 13, 2007 - link

    It was a nice article. I know not to buy this PSU now when I build my roommates computer later this month. I don't like how it falls out of spec at high loads. I would like to see a review on the PC P&C 750W Silencer Quad, as that was what I was planning on using for his computer.

    Looking at that board frightened me, seeing as how much power was in that supply, and how close together the components were. I hope that they can increase the size of the standard power supply to help alleviate this problem now that we are building computers that have such high loads. I used to design and test power supplies (albeit for automotive conponents) and seeing how they crammed those parts so close together was scary. That is an easy way to kill the reliability and life of your supply. The heat just kills the board and components. Although it does reduce problems like parasitic capacitance. Maybe that is why many manufactures are avoiding using the top mounted 120mm fan; to keep from having to package the component like that.
  • yacoub - Friday, July 13, 2007 - link

    quote:

    If you leave the PC off for a long period of time, you should still always hit the switch or unplug the cable.


    But doesn't that mean the motherboard will need to use its little battery backup to keep the BIOS settings? Turning off the PSU switch and/or unplugging the cable to fully remove power sounds like a way to kill your motherboard's battery quickly.
  • mindless1 - Wednesday, July 18, 2007 - link

    It is only a "suggestion", there is just as valid an argument to not unplug it unless you're on a quest to save every last bit of power possible which is a nobile goal but put in perspective, a bit of a band-aid since anyone using a modern computer to access webpages is wasting orders of magnitude more power, even ignoring the typical products with large power consumption.

    It might be said that unplugging also provides some protection against surges, limiting exposure to them, but it's really something that would have to be considered on a per-site basis, remembering that most people don't unplug their computers any day of the year and seldom is surge damage a recurring problem. IOW, a matter of how much extra effort to put forth to guard against something that, statistically, isn't likely to happen.
  • DerekWilson - Friday, July 13, 2007 - link

    iirc, your mobo battery is in use when the computer is off and the PSU is on anyway. i could be wrong ... its been like a decade since i paid attention to that.

    But either way, mobo batteries last years even when their not powered up.
  • SpaceRanger - Friday, July 13, 2007 - link

    Very nice work on AT's first PSU review with such detail. One question though, what happened to the Ripple and Noise results from the PSU? In the methodology they were mentioned to be tested, yet not in this review?

    Looking forward to more PSU reviews..
  • Shadowmage - Friday, July 13, 2007 - link

    I agree. The reviews must have ripple. That's why Jonnyguru's reviews are so highly regarded.
  • mindless1 - Wednesday, July 18, 2007 - link

    and yet, we don't really need to know the ripple values so long as they stay within ATX specs at the max rated loads and all crossloading combinations possible. Within these limits, lower ripple is not necessarily "better" per se, if it were important to have lowest possible ripple we wouldn't be using switching PSU at all or they'd at least have an addt'l stage of LC filtration before the output.
  • LTG - Friday, July 13, 2007 - link

    The first page leaves out an explanation of why multiple rails are used in the first place.

    I'm sure many technical software people, who don't know hardware, wonder like I do, why wasn't it always just one rail?

    Just a couple sentences would probably be helpful.

    thanks.
  • qpwoei - Friday, July 13, 2007 - link

    A PSU having multiple rails just means that a single rail in the PSU runs through a number of parallel current limiters - so all lines on the 12V1 rail go through one 20A current limiter, all lines on 12V2 go through another, etc. This is done as IEC safety requirements (and consequently ATX PSU requirements) say that "operator accessible" connections must not be able to deliver more than 240 VA (ie: 20 A at 12 V).

    In older PSUs, only a single current limiter was used as there was no requirement for maximum current per line. In many recent PSUs, the single current maximum is starting to come back as well due to the high current requirements of modern GPUs and motherboards.
  • mindless1 - Wednesday, July 18, 2007 - link

    While it is common (because it's cheaper to implement) for a 12V multi-rail PSU to use parallel current limiters, it is not necessarily true that all are designed this way, typically only those built towards lower component cost instead of higher sustainable current. Other options include having separate capacitance after the current limiter (resistor), or a second inductor-cap LC stage, or additionally a separate rectifier stage, or additionally a separate transformer (essentially going backwards towards building in a 2nd supply until available space and budget limit it).

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