EVGA SuperNOVA 850 T2 Power Supply Review

Transient Response Tests

Advanced Transient Response Tests

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

In these tests, we monitor 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) is applied for 200ms while the PSU works at 20 percent load. In the second scenario, the PSU is hit by the same transient load while operating at 50 percent load. In both tests, we use our oscilloscope to measure the voltage drops caused by the transient load. The voltages should remain 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 or an instant 100 percent load of CPU/GPUs). We call them "Advanced Transient Response Tests," and they are designed to be very tough to master, especially for PSUs with less than 500W capacity.

Advanced Transient Response at 20 Percent

VoltageBeforeAfterChangePass/Fail
12V12.226V12.192V0.28%Pass
5V5.033V4.919V2.27%Pass
3.3V3.309V3.159V4.53%Pass
5VSB5.082V5.047V0.69%Pass

Advanced Transient Response at 50 Percent

VoltageBeforeAfterChangePass/Fail
12V12.197V12.162V0.29%Pass
5V5.017V4.905V2.23%Pass
3.3V3.296V3.148V4.49%Pass
5VSB5.058V5.025V0.65%Pass

As we'd expect from a Leadex platform, deviations on the +12V rail are minimal. The same applies to the 5VSB rail. Unfortunately, the minor rails don't perform as well. The 3.3V rail registers the worst performance, with close to 4.5% deviations in both tests. Its voltage drops dangerously close to the ATX specification's lower limit during the second test. 

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 measure the PSU's response in simpler transient load scenarios—during its power-on phase.

For the first measurement, we turn off the PSU, dial in the maximum current the 5VSB can output and switch on the PSU. In the second test, we dial the maximum load the +12V can handle and start the PSU while it's in standby mode. In the last test, while the PSU is completely switched off (we cut off the power or switch off the PSU by flipping its on/off switch), we dial the maximum load the +12V rail can handle before switching on the PSU from the loader and restoring 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).

The 5VSB rail registers a small spike that's way below the limit, while the +12V slope is perfect in both tests. Overall, we see very good performance here. 

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  • turkey3_scratch
    Very great unit, as expected. I would have liked to see the threshold for when OTP really kicks in, if it even does. Perhaps duct taping the exhaust grill will do the trick. It's nice to see Superflower use a MOV for a change. I just wish that 3.3V rail would not get so near 3.14V during the transient response tests, but realistically I don't expect the 3.3V rail to get that sudden load these days.

    Also @Aris, are you sure there's only 4 y caps? I thought those blue sleeves store multiple y caps? Or do they not?
  • damric
    That's some yummy low ripple for overclocking.
  • Aris_Mp
    if you mean the blue components before/after the bridge rectifier, they are X caps and I didn't count them in the EMI filter on purpose.
  • ZeusGamer
    I've had the G2 model of this power supply and it's still working great after two years. I'm really impressed by EVGA with these G2 and T2 models.
  • JackNaylorPE
    Efficiency is nice... I guess .... but with that 3.3 and 5V performance, I'm not impressed.
  • Dark Lord of Tech
    3.3 rail can vary per unit doesn't worry me a bit.
  • Dark Lord of Tech
    3.3 rail can vary per unit , doesn't worry me a bit. Every test model for a review can produce different results.
  • JackNaylorPE
    To each his own I guess... but for the ridiculous price of $240, I'd want better. The Corsair 860 and coolermaster V850 PSUs finish 1 and 2 and are much cheaper.

    The unit would fail to meet the ATX spec at 5%, and this comes in at a rather dismal 4.5 %... yes, this does vary from unit to unit (and this is a bad thing) If the unit that winds up in the hands of a review site gets two outta 3 rails at 4.5%, I shudder to think what we might get ordering off newegg. In the review graphs, it's the bottom of the chart against all the other PSUs with which its compared.

    The focus on efficiency in the ranking of PSUs in an enthusiast box is a criteria which escapes me ... I never walked into a Porsche dealership where the salesman's first pitch was "this model is great, it has the best gas mileage in our entire line'.
  • yyk71200
    Differences in effissiency between gold, platinum, and titanium psus are rather small and do not justify price differences. Quality of output is more important criteria in choosing a psu than small differences in wattage consumed.
  • JackNaylorPE
    ^^ ^^
  • turkey3_scratch
    It's $240? Yeah, I'd never see myself purchasing this at that price point. I do see myself purchasing the Seasonic Snow White perhaps some time in the future. I'm with JackNaylorPE, I don't really care about efficiency, but it does have impressive efficiency, still. But as for that 3.3V rail, in a normal system there is not going to be a sudden 5A increase on this rail! RAM only primarily uses 3.3V today, I know GPUs do some and probably some other minor things, but realistically this won't happen. From my personal opinion, though, I want a PSU that can handle anything and everything well, and for $240 it doesn't meet my expectations of that.

    I love the Tomshardware tests because Aris tests things other reviewers do not. I find that no unit manages to perfectly glide over everything. Oh, and I'm happy with the holdup time on this unit, too. But the price of this is far too high. Make it $150-$160 and then we're talking.
  • JackNaylorPE
    And the 1050 snow just barely breaks $200 ... 750 is $160

    The 750 / 1080 snow topped out at 2.8

    Tho it must also be said that below a certain point, you don't get any additional gains to the extent that there will be no measurable impact. I'm happy if I can reduce temps say from 75 to 73 ... but don't really feel I have gained anything by going from 72 to 71.9 At some point, ya gotta ask is there a reason to care ? But when the Corsair CX600m scores 4.64% and the best this $240 PSU can do is 4.5%, I don't feel it's "got the complete package".
  • Dark Lord of Tech
    Decent price! :D

    Ordered 2 , lets see how they perform for my future builds.
  • techgeek
    In the one close up picture of the daughterboards, it looks like U3 met with a catastrophic failure. It looks like it popped and half of it is missing? Can you confirm?
  • babernet_1
    Quote:
    In the one close up picture of the daughterboards, it looks like U3 met with a catastrophic failure. It looks like it popped and half of it is missing? Can you confirm?


    The U3 is actually not installed.
  • techgeek
    I'm not sure you are looking at the same picture I am. There is clearly half a component there, I presume a FET, but there doesn't look like there is enough to make out.
  • Virtual_Singularity
    Awesome power supply unit, if a bit pricey. Go Superflower!! And btw, excellent review Aris. I've noticed the psu reviews on this site have become more thorough and comprehensive lately. Much appreciated and good job.
  • Aris_Mp
    There is no U3 FET installed on the +12V boards.
  • techgeek
    1903369 said:
    There is no U3 FET installed on the +12V boards.


    I had another look, I think its just dirty there, and an imprint in the solder mask / conformal coating there that makes it look like half a component. I can see the solder lands on both sides now. Just looked odd. The 'dirly' spot looked to me like where a FET had blown up and half had chipped away. I've seen this type of failure a few times, so I thought that maybe this was one of these occasions.