Enermax Revolution SFX 650W PSU Review

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Final Analysis

Enermax chose to enter the SFX market with two models based on CWT's CSN platform. Their power density is quite high and the build quality is good. However, the performance of Enermax's ERV650SWT doesn't live up to our expectations. We'd like to see higher efficiency levels under normal loads, too.

Corsair's SF line-up, based on a Great Wall platform, sets a high bar for SFX power supplies. We know it's harder for these small PSUs to achieve similar performance as larger ATX models, but we want to see new products at least match the existing competition.

The strongest Enermax SFX PSU is fully modular. Unfortunately, though, it's equipped with an 80mm fan. To make matters worse, the fan profile is fairly aggressive, resulting in a lot of noise under moderate loads. A larger 92mm would have helped by moving a similar volume of air at lower RPM. It's only at light loads and under normal operating temperatures that the ERV650SWT's acoustic profile is acceptable. Most enthusiasts will find the noise annoying at higher load levels.

Due to limited space, CWT doesn't give this power supply a power switch. In our opinion, though, every PSU should have a power switch.

Load regulation is decent overall, and ripple suppression at +12V is quite good. The hold-up time we measured is really low, though (under 8ms). Of course, the ERV650SWT's PCB is small, leaving little room for a larger bulk cap or two in parallel. But we think CWT should adjust its design accordingly to accommodate larger bulk caps.

Although the +12V rail's transient response is good for an SFX unit, the 3.3V rail's performance is lousy in the same tests. Meanwhile, the 5VSB rail's efficiency is remarkable, showing that CWT paid extra attention to it at a time when other manufacturers are failing to update their 5VSB regulation circuits. The 80 PLUS program might not measure the 5VSB rail's efficiency, but it's still important. The same applies to vampire power.

With a small adjustment to the Revolution SFX 650W's price tag, Enermax would have an easier time competing against other PSUs in this category. A longer warranty would also help, especially since the competition more than doubles what Enermax offers. But a sleeve-bearing fan makes it difficult to go much beyond five years of coverage or so. We'd like to see Enermax use a larger fan with a more reliable bearing; this would solve a lot of the ERV650SWT's issues. It'd also be nice to see Enermax relocate the transient filter's PCB. Where it's installed now totally blocks airflow to the secondary side, making life difficult for a number of sensitive electrolytic capacitors.

Update, 7/21/17: Enermax informed us that the warranty of the product is actually five years long, although at the moment of the review Newegg lists it with a three-year warranty.

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Contributing Editor

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

  • shrapnel_indie
    How many motherboards require more than one EPS connector in the entry to enthusiast level motherboards (excluding server boards)? How many server boards? How many enthusiasts actually use server boards?

    IMHO, if a PSU has 1 or 2 EPS connectors shouldn't be a pro or con as the vast majority of boards used from entry level to enthusiast only really requires one connector. Server boards are a different matter. IMHO, just making a clear note how many EPS connectors should be good enough.
    I can see wanting more than 2 PCIe of course, but how many SFX models come with 2 EPS? How many dual CPU micro atx mobos are there anyway?
  • Ne0Wolf7
    Why would you ever want there not to be a power switch? I use mine all the time... It seems like such a simple thing to add too.
  • 10tacle
    ^^That's the first thing I noticed in the pictures. I use mine on occasion too, especially when getting lockups during overclock testing. Flicking a switch is a lot more convenient than reaching around and unplugging and making sure the cable doesn't fall down behind the desk causing colorful four letter language. Unwise omission that is inexcusable in this category of PSU. I would rule out this PSU just for that omission alone.

  • Aris_Mp
    about the two EPS connectors, most mid to high-end mainboards use one EPS and one ATX12V (so they need two CPU connectors) especially the new ones. Why not have this option and be restricted to mainstream mainboards. Not only server or dual CPU mainboards require two EPS connectors.
  • Marcus52
    Enermax still hasn't recovered their quality since they shut down their own production facilities, which is a real shame, they used to be one of the best.
  • superflykicks03
    You guys literally have ads that play over the top of your intrusive popup videos. You literally have to watch a 30 second ad before you get to watch the unwanted video :/ Not exactly user friendly. I know I know revenue blah blah, and just get a popup blocker yadda yadda.
  • maxwellmelon
    Why would you turn off the power on the power supply on computer lockup. Just hit the reset switch. I would venture to say 9 out of 10 people could care less as there pc is always on.
  • 10tacle
    Because hitting reset from the case button does not guarantee a solid reboot. On my system anyway.
  • warmon6
    For an SFX psu, not having a power switch on the PSU doesn't bother me to much.

    Depending on the case design (like my rvz01), you couldn't access the psu without taking the computer apart to access that switch. So unplugging the computer or holding the power button for 5 seconds would be a lot faster.

    Now if this was an ATX PSU i would give a bit more care for as it's extremely rare for an ATX psu to be placed somewhere else inside the case that cant be access from the outside.


    I do have to ask though, does your computer lock up so much that even holding the case power button for the 3 to 5 seconds does nothing?

    Most computers I've messed with seems to be able to power off fully even when there is a hard lockup doing that method.

    But i do agree with you about that hitting a reset doesn't guarantee a solid reboot. Certainly when trying to dial in overclock settings.