EVGA SuperNOVA 550 GS PSU Review

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Transient Response Tests

Advanced Transient Response Tests

For details on our transient response testing, please click here.

In these tests, we monitored the response of the PSU in two different scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V and 0.5A at 5VSB) was applied to the PSU for 200ms while the PSU was working at 20 percent load. In the second scenario, the PSU was hit by the same transient load while operating at 50 percent load. In both tests, we used our oscilloscope to measure the voltage drops caused by the transient load. The voltages should have remained within the ATX specification's regulation limits.

These tests are crucial because they simulate the transient loads a PSU is likely to handle (such as booting a RAID array, an instant 100-percent load of CPU/GPUs, etc.). We call these tests "Advanced Transient Response Tests," and they are designed to be very tough to master, especially for a PSU with a capacity of less than 500W.  

Advanced Transient Response at 20 Percent

Swipe to scroll horizontally
VoltageBeforeAfterChangePass/Fail
12V12.199V12.052V1.21%Pass
5V5.072V4.944V2.52%Pass
3.3V3.341V3.216V3.74%Pass
5VSB5.053V5.014V0.77%Pass

Advanced Transient Response at 50 Percent

Swipe to scroll horizontally
VoltageBeforeAfterChangePass/Fail
12V12.136V12.013V1.01%Pass
5V5.038V4.891V2.92%Pass
3.3V3.304V3.186V3.57%Pass
5VSB5.008V4.968V0.80%Pass

Voltage deviations were well controlled on all rails and were within the range that we expected from a solid mid-capacity PSU. Of course, we would like to have seen measurements within a three percent deviation at 3.3V, but if you check the corresponding graph, you will notice that even PSUs based on high-end platforms (like the Seasonic SS-520FL) don't always achieve this, so we cannot have high expectations from a mid-range unit.

Here are the oscilloscope screenshots we took during Advanced Transient Response Testing:

Transient Response At 20 Percent Load

Transient Response At 50 Percent Load

Turn-On Transient Tests

In the next set of tests, we measured the response of the PSU in simpler transient load scenarios—during the PSU's power-on phase.

For the first measurement, we turned off the PSU, dialed in the maximum current the 5VSB could output and switched on the PSU. In the second test, we dialed the maximum load the +12V could handle and started the PSU while it was in standby mode. In the last test, while the PSU was completely switched off (we cut off the power or switched off the PSU by flipping its on/off switch), we dialed the maximum load the +12V rail could handle before switching on the PSU from the loader and restoring the power. The ATX specification states that recorded spikes on all rails should not exceed 10 percent of their nominal values (+10 percent for 12V is 13.2V, and 5.5V for 5V).    

Besides a small bump and two short periods of increased ripple during the last test ("PSU off to Full 12V"), the PSU performed pretty well. As you can see from the above scope shots, the slopes in the first two tests were close to perfect.

Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • damric
    There are less rippletastic options at that price point.
    Reply
  • Nuckles_56
    Nice to see a review of a smaller ATX PSU for a change
    Reply
  • Aris_Mp
    my last reviews were of smaller capacity units and I will try to bring even more of them.
    Reply
  • Luay
    Coorection, EVGA did release a gold rated 1050W and 850W Seasonic PSU also branded as GS, and a platinum 1000W PS. There's also a 650W version of the PSU reviewed here which takes the total to five Seasonic OEMs branded by EVGA.
    Reply
  • Larry Litmanen
    There are less rippletastic options at that price point.

    For the most part when it comes to PC parts you get what you pay for. Unless you spot a great sale, a 550W fully modular, 80 Gold PSU from a company like EVGA with a 5 year warranty. EVGA is super easy to deal with should you need to replace a unit. All that for $90? If this PSU was a 650W unit with same features and for the same price it would have been perfect.
    Reply
  • atheus
    There are less rippletastic options at that price point.

    For the most part when it comes to PC parts you get what you pay for. Unless you spot a great sale, a 550W fully modular, 80 Gold PSU from a company like EVGA with a 5 year warranty. EVGA is super easy to deal with should you need to replace a unit. All that for $90? If this PSU was a 650W unit with same features and for the same price it would have been perfect.
    You mean the price would have been perfect? Confusing idea to change the wattage rather than just change the price. I take that to mean instead of a certain price/performance you would rather have a 650 watt PSU than a 550.

    I see 650 watt PSU's as only for SLI systems, which are fairly niche. With 550 you can handle any single GPU, and in the case of Maxwell GPU's <= 980 you could even SLI them so long as you aren't doing some obscene overclocking or running a dozen fans and pumps and a datacenter worth of HDD's. So for my go-to wattage for a standard high performance single GPU build is 550. For medium performance 450 is even better.
    Reply
  • Dark Lord of Tech
    I own this one great modular power supply.
    Reply
  • logainofhades
    Unless you really feel the need for a gold rated PSU, I would probably save some cash and stick with a Seasonic 520w or 620w M12II. Even the 750w B2 series is cheaper.
    Reply
  • Aris_Mp
    Coorection, EVGA did release a gold rated 1050W and 850W Seasonic PSU also branded as GS, and a platinum 1000W PS. There's also a 650W version of the PSU reviewed here which takes the total to five Seasonic OEMs branded by EVGA.

    This is exactly what I write inside the review. Four GS PSUs and one PS.

    "So far, the new PS series includes only a single unit with 1kW of max power; EVGA's GS line, on the other hand, has four PSUs with 550, 650, 850 and 1050W capacities."

    I also have the 650 GS in my lab, but this isn't for Tom's.
    Reply
  • Coolant
    Quick question, what would happen if one of the secondary fets was removed?
    Reply