FSP Twins 500W Redundant PSU Review

Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

Pros, Cons, And Final Verdict

We have mixed feelings about the Twins 500W. For starters, we like the idea it's built on. However, the actual implementation could be better with some changes. If FSP provided the option to completely deactivate one module and not use both of them in parallel, then efficiency under light loads would improve significantly. In addition, there would be minimal stress applied to the module in standby, bolstering its reliability. By having both modules operate simultaneously, they endure the rigors of always-on operation, increasing the possibility that they break down at the same time, or at least close together. Given that FSP implemented a digital platform, the right modifications to hardware and software could enable FSP's Guardian app with controls to deactivate this hybrid module operation. Hopefully we see something like this in the family's next revision.

FSP's Twins 500W is an interesting PSU. It's the first server power supply designed to fit in normal ATX cases, addressing enthusiasts who need a highly reliable PSU for their home servers. The build quality is pretty good, and FSP uses top-notch components to ensure the frame and modules enjoy a long lifetime.

The major problem most folks are going to have with the Twins 500W, aside from its steep price tag, is the noise generated by those small fans in the modules. For a server system typically installed in a noisy environment, this doesn't pose a problem. But in a PC that lives in your house, that's a major con. So before you decide to invest in this PSU for a home server, take into account that it will definitely make its presence felt, especially under tough workloads. You'll want to find an isolated space for it. Conversely, if you're adverse to all of that noise, buy a high-quality desktop PSU instead and forget the redundant functionality.

Performance-wise the Twins 500W doesn't set any records, especially when it comes to load regulation and ripple suppression. But we can't forget that it belongs to a special PSU category, so comparisons to normal desktop PSUs are inherently unfair. This is a server-type unit offering increased reliability and a rich feature set attributable to its digital circuit, which facilitates monitoring via software.

We would like to see FSP use more PCIe connectors, ideally four of them, along with additional SATA connectors. You might counter that a server PSU won't be used in a gaming system, so two PCIe connectors are enough. Still, this is a server PSU addressing home users, so you never know where it'll end up. Finally, it would be nice if the next Twins generation also offered some modular cables as well. Meanwhile, we are expecting the second member of this line with increased capacity, the Twins 700W, to hit the market pretty soon.

MORE: Best Power Supplies

MORE: Power Supplies 101

MORE: How We Test Power Supplies

MORE: Picking The Right Power Supply: What You Should Know

MORE: Computer History: From The Antikythera Mechanism To The Modern Era

MORE: All Power Supply Content

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • shrapnel_indie

    Full power at 45°C
    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.)

  • 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?
  • 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.
  • 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.
  • 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...
  • 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.
  • 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).
  • PsiReaper
    A perfect PSU upgrade for my UnRAID box..
  • shrapnel_indie
    19144735 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.)

  • 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?