FSP Twins 500W Redundant PSU Review

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. 

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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.

Our hold-up time result is very long since the bulk caps of both modules are utilized in this test. On top of that, we need to see a large number for a smooth transition to take place from one module to the other in case of a failure.

Inrush Current

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

The inrush current is quite low with 115V input, while it's on the high side with 230V (still, we see less than 50A).

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the Twins 500W's efficiency. The applied load equals (approximately) 10 to 110 percent of the PSU's maximum load 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 0.1A. This test 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.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed
Fan Noise
Temps (In/Out)PF/AC Volts
12.337A1.995A1.988A0.990A49.7567.540%8233 RPM
53.8 dB(A)
37.05°C0.939
12.056V5.005V3.316V5.049V73.6640.97°C115.1V
25.726A3.001A2.990A1.190A99.7478.498%8782 RPM55.3 dB(A)38.99°C0.970
12.033V4.986V3.307V5.032V127.0643.43°C115.1V
39.471A3.515A3.514A1.395A149.8482.945%8844 RPM55.6 dB(A)39.16°C0.978
12.013V4.973V3.298V5.013V180.6543.82°C115.1V
413.224A4.034A4.009A1.600A199.7985.260%9124 RPM55.2 dB(A)39.44°C0.986
11.992V4.962V3.291V4.995V234.3344.60°C115.1V
516.646A5.052A5.029A1.805A249.7486.466%9294 RPM54.9 dB(A)39.89°C0.989
11.972V4.945V3.279V4.977V288.8345.52°C115.1V
620.082A6.090A6.055A2.015A299.7187.120%9609 RPM54.7 dB(A)40.52°C0.991
11.947V4.928V3.268V4.958V344.0246.43°C115.1V
723.524A7.126A7.084A2.225A349.7287.371%9836 RPM52.2 dB(A)41.14°C0.993
11.930V4.912V3.259V4.940V400.2747.53°C115.1V
826.992A8.180A8.127A2.436A399.7687.408%10316 RPM50.4 dB(A)41.98°C0.994
11.905V4.894V3.249V4.920V457.3548.73°C115.1V
930.915A8.711A8.673A2.440A449.7387.406%10718 RPM51.6 dB(A)42.88°C0.995
11.875V4.882V3.240V4.911V514.5350.12°C115.1V
1034.551A9.248A9.192A3.075A499.6787.196%11062 RPM52.5 dB(A)43.90°C0.996
11.865V4.869V3.231V4.877V573.0451.63°C115.1V
1138.834A9.258A9.211A3.078A549.6187.074%11556 RPM54.8 dB(A)44.62°C0.997
11.843V4.863V3.223V4.870V631.2052.90°C115.1V
CL10.099A16.026A16.004A0.004A131.3275.947%14706 RPM53.5 dB(A)43.43°C0.976
12.011V4.863V3.260V5.091V172.9147.57°C115.1V
CL241.624A1.004A1.003A1.002A507.2588.205%11013 RPM52.5 dB(A)44.03°C0.996
11.868V4.955V3.264V4.997V575.0851.42°C115.1V

Load regulation at +12V is satisfactory, but it's quite loose on the minor rails. Apparently, the frame's DC-DC converters need some modification in order to offer tighter voltage outputs.

Efficiency under light loads is pretty low because the output of two PSUs is combined, doubling their power losses. Moreover, under high ambient temperatures, both fans are quite loud. We also notice a fan bearing noise in the 8000-10,000 RPM range. For those of you who weren't expecting such high acoustic readings, remember that this is a server-class PSU running under tough conditions. In addition to costing more money, professional power supplies delivering increased reliability and redundant functionality also tend to be loud. If you don't want a noisy PC, stay away from this FSP offering.

FSP Guardian Screenshots

You will find several screenshots of the FSP Guardian software below.

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    Your comment
  • shrapnel_indie
    Quote:

    Pros

    Full power at 45°C

    Quote:

    All cables are fixed, and because this is a server-like product, its maximum operating temperature for continuous full power delivery is 50°C.



    Please explain to me why these numbers don't seem to match up properly. (THB, I may have missed it.)
    0
  • dstarr3
    I really wonder what a consumer could possibly want this for. What is an ordinary consumer doing that they absolutely cannot risk any downtime whatsoever on their rig?
    1
  • nzalog
    I know freenas can be configured to work faster if you can for sure trust the system from not having RAM errors (covered by ECC) and if you can guarantee there is no unexpected shutdown (covered by dual power and ups). However the reliable power is not really required because a SSD as an SLOG device will cover for it, but then the SSD becomes the bottleneck for writes.
    0
  • firefoxx04
    I build several file servers a month for clients. Low end enough to where pre built solutions are not an option. This power supply would be a good fit but it is useless, imo, without some sort of email alert option. Maybe I missed that?

    When I deploy file servers for clients, I always setup some sort of alert system for raid failures so I can fix the problem. What is the point of redundancy if the user has no idea a problem has occurred? Yes i know that this PSU makes a "loud buzzer noise" but I cant have that either. The user needs to continue to use the system and they cannot if it is screaming 100% of the time.

    Send me an email alert. Its easy to implement.
    0
  • Rookie_MIB
    One thing I'm curious about - what if one unit does fail? Are they bog-standard replacement parts where you can go and buy a similar hot swap redundant power supply or is the system proprietary. If it's the latter, then I don't see many people lining up for this one...
    3
  • apache_lives
    A PSU is but one part of a "reliable" machine, to me this will not increase up time or do anything of any value, seems more like a "makes me feel better" part.
    0
  • Aris_Mp
    about the first comment, the PSU is certified for up to 50C ambient full power delivery, but I choose to test up to 45C every PSU that passed from my test bench (since I also have to evaluate 40C rated units and I need to keep the same conditions for all).
    1
  • PsiReaper
    A perfect PSU upgrade for my UnRAID box..
    0
  • shrapnel_indie
    Anonymous said:
    about the first comment, the PSU is certified for up to 50C ambient full power delivery, but I choose to test up to 45C every PSU that passed from my test bench (since I also have to evaluate 40C rated units and I need to keep the same conditions for all).


    While I'm glad for that, It's also nice to know if a unit rated at 50°C operation will deliver on its "promise" though. (If you exceed the "promised" rating, like the 40°C rated units @ 45, well, it delivered on its promise and then some.)
    0
  • Pompompaihn
    Newegg has several server chassis for sale that come WITH redundant 500w+ PSUs for less money than just this power supply. Given that the market is low end commercial/prosumer, and it's not going to be for gaming or HTPC, why wouldn't you just buy the whole thing for cheaper?
    1
  • Matel Onely
    Another issue with this is replacement. My server is up out of the way and a real pain to get to. I'd absolutely do not move it if it is powered on. So to replace the power supply I'd probably power it down anyway.

    what they should really do is one of two things
    1) Design it to fit into a DVD drive bay (or two). That way you can pull the broken power supply from the front which is mostly likely easily accessible. Most ATX towers have multiple DVD bays that end up not being used if they are servers.

    2) The second option, and more expensive solution, would be to design an ATX tower where the power supply sticks out the front. Again for easy access for folks using standard ATX type cases.

    Look in a server room. The power supplies are easy to get to. Of course the server racks are also accessible from either the front or back. But they are made for maintenance. To simplify maintenance for ATX cases, some tweaks will have to happen to really make use of these types of power supplies.
    1
  • dstarr3
    Anonymous said:
    Newegg has several server chassis for sale that come WITH redundant 500w+ PSUs for less money than just this power supply. Given that the market is low end commercial/prosumer, and it's not going to be for gaming or HTPC, why wouldn't you just buy the whole thing for cheaper?


    System building rule #1: If your case comes with a PSU, throw it away immediately, because it WILL be rubbish. Server chassis are no exception.
    0
  • drajitsh
    I also noted the discrepancy in temp
    0
  • drajitsh
    I wonder if it is possible to make an intelligent pass through board for connecting dual power supplies. A lot of full tower cases have space for 2 power supplies and you could use a standard ATX power supply.
    0
  • maxwellmelon
    not truly fail safe " DC-DC converters for the minor rails " are not independent so though they may be reliable then the higher voltage side I have seen plenty of 5 volt regulators fail. if it fails the system fails as though the 12 volt rail has two independent options powering it the lower voltages do not. that is a flaw in good redundancy. i have seen plenty of failures of 5 volt dc-dc converters on tvs boards while the 12 volt generation of the switching power supply was still working correctly/cleanly. would have just been nice to see a true dual power supply.
    0
  • mcgyver2822
    It would have to come with a schematic and parts list to enable repair., because at $400 you will want to keep it a very long time., otherwise no one is going to discard a $400 PSU..
    0
  • I
    Niche market results in price way too high for what it is. Back in the day I just put two full ATX in a full tower case with ORing diodes. Yes you lose a few tenths of a volt, but total cost was only $40 per PSU, $10 for diodes, and I used misc PCB, wire and connectors I had lying around or cannibalized. Granted I can't count those parts as FREE, but I can count them as a heck of a lot less than $310 dollars worth.

    Except for taking up twice the space it was a better setup too because if one PSU failed I could source a standard replacement PSU locally except that I already had a spare. A typical consumer isn't going to have spare $400 PSUs lying around.
    0