Seasonic Snow Silent 750W Power Supply Review

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 200 milliseconds 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 that a PSU is likely to handle (like booting a RAID array or an instant 100 percent CPU/GPU load). 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

VoltageBeforeAfterChangePass/Fail
12 V12.133V12.050V0.68%Pass
5 V5.031V4.966V1.29%Pass
3.3 V3.348V3.258V2.69%Pass
5VSB5.095V5.060V0.69%Pass

Advanced Transient Response at 50 Percent

VoltageBeforeAfterChangePass/Fail
12 V12.121V12.044V0.64%Pass
5 V5.027V4.963V1.27%Pass
3.3 V3.345V3.254V2.72%Pass
5VSB5.060V5.016V0.87%Pass

The unit easily handled all of the hurdles we threw at it, showing that, besides excellent load regulation, it also has a great response in transient loads that come close to real-life conditions. A PSU will need to handle transient loads for most of its lifetime, so good performance in these tests is significant.

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 that the 5VSB could output and switched on the PSU. In the second test, we dialed the maximum load that 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 that 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).    

The 5VSB rail took a little longer than usual to reach the nominal voltage, but it still did so in less than 20ms as the ATX spec dictates. In the other two tests, the slopes didn't ramp up smoothly. We noticed some spikes, but they weren't high enough to make us worry. These results were not top-notch, but we can't call them bad or even mediocre.

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  • dragget
    "Unfortunately, the on/off switch for toggling hybrid mode is located on the back side of the PSU, so accessing your system's internals becomes necessary if you want to change fan modes."
    Most likely they did it this way to avoid having two switches on the outside face of the PSU. If they had placed both switches there I can see people reaching around the back of their case to change fan modes and accidentally turning off their PC because they flipped the wrong switch.
  • g-unit1111
    This would look awesome in my H440!
  • Adroid
    Yea to be honest I prefer the fan/hybrid toggle on the INSIDE of my case anyway. I put my Seasonic Platinum 650W in hybrid mode a long time ago and forgot about it.

    I don't see any need to flip the switch on and off, in fact I can't think of a single good reason why I would ever want to touch the thing again. So for me, it would be a con to have the switch on the outside of the case.
  • Aris_Mp
    this switch is much smaller than the on/off one so it is really hard to mix them up. Also the on/off switch is harder to activate. In any case as a reviewer I see this as a con, not a serious though. Some users out there will share my opinion while others won't.
  • dragget
    Quote:
    this switch is much smaller than the on/off one so it is really hard to mix them up.

    If you were looking at the back of the PSU, then yes, but I'm assuming the more common situation where the user is reaching around the back of the case where they can't see. In this scenario, one would have to feel around the back with their hand so it's much easier to get it wrong. I almost never use the switch on the back of my PSU, so every two or three months when I DO use it, I have to fumble around in the back to find the switch. For your average user, having two switches back there would just be asking for trouble.
  • MasterDell
    A lot of companies are putting the hybrid switch on the inside of the PSU. Just like the new units EVGA is putting out. It makes no sense to put the switch on the outside due to confusion with the on/off switch
  • LookItsRain
    180 dollars for this? No.
  • JQB45
    I'd pay $150-$180 USD for this PSU and not just because its pretty.
  • dstarr3
    Quote:
    180 dollars for this? No.


    For a rock-solid PSU with a 7-year warranty? This thing would power my next three or four computers. $180 for not having to buy another PSU for a decade is a damn good deal.

    Regarding the fan switch, my PSU has a similar feature, and honestly, I imagine most people would set it at installation and never change it. I sure haven't.
  • Aris_Mp
    Indeed a PSU is an investment, something that unfortunately most people cannot see or understand while on the same time they have no problem spending serious money on GPUs and CPUs.

    You can keep a good PSU for many system builds while a not reliable, cheap PSU besides breaking down fast can also destroy many of your system components.
  • JackNaylorPE
    Been looking for this on jonnyguru.... the 1050 watter scored a 10 in build quality and performance. My son bought the 1000 G2 cause it was cheaper than the 750 at the time.... the 1000 G2 is way too dang noisy. This wuda been nice.
  • LookItsRain
    68185 said:
    I'd pay $150-$180 USD for this PSU and not just because its pretty.


    I paid 54 dollars for a psu that its damn near the same quality.
    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=393

    This psu in this review is horrendously overpriced.
  • MasterDell
    1333631 said:
    68185 said:
    I'd pay $150-$180 USD for this PSU and not just because its pretty.
    I paid 54 dollars for a psu that its damn near the same quality. http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=393 This psu in this review is horrendously overpriced.

    Getting a good deal on a PSU that was released a while ago is one thing. That PSU had and has an MSRP of $90. Not $54. It's also bronze rated. Not saying that is a bad thing or a relevant thing, but efficiency does affect the MSRP of PSU's.
  • JackNaylorPE
    1. The current price is MSRP and will hold until there's some competition from vendors. The 1050 came out at $255 ... its $202 now; once there are enough supplies in the channel, it will be $139-$144 ... probably less

    2. My son has a 1000 watt G2, I'd pay $50 if I didn't have to hear that fan all day, The G2 matched the performance and it's $105, the HX750i is surely worth the extra $10... The Antec HCG matches the BQ and it's $85

    3. But like anything else, if you want that binned GPU, the best overclocking MoBo, the price premium suffers from the law of diminishing returns. Michael Phelps made millions coming home from the Olympics with Gold Medals .... how much did the guy with the silvers make ?

    4. It is damn perty :)

    A real nice street racing engine might cost ya $15k .... wanna take 2/10's of a second off that and ya can spend $50k
  • g-unit1111
    1903369 said:
    Indeed a PSU is an investment, something that unfortunately most people cannot see or understand while on the same time they have no problem spending serious money on GPUs and CPUs. .


    Yeah exactly it's an investment as much as the actual PC itself is. And I've seen enough builds on this site where I almost instantly recommend that people spend more money on a PSU. You're paying $350 for an i7 and $600 for a GTX 980TI, yet you won't pay more than $75 for a Corsair CX750. I mean WTF??? Like 99% of the time on this website the answer to most people's problems with their system is "buy a new PSU". And it is really sad when people don't see that's a huge investment.

    Quote:
    Been looking for this on jonnyguru.... the 1050 watter scored a 10 in build quality and performance. My son bought the 1000 G2 cause it was cheaper than the 750 at the time.... the 1000 G2 is way too dang noisy. This wuda been nice.


    I have both 850W and 750W versions of the G2 and I've never seen an issue with either one in regards to noise.
  • junkeymonkey
    lots of folks just don't see a psu is the hart and life blood of a build and top stable build quality goes a long way.. spend 2000 bucks on a build and 64.95 on a psu .
  • JackNaylorPE
    537231 said:
    Yeah exactly it's an investment as much as the actual PC itself is. And I've seen enough builds on this site where I almost instantly recommend that people spend more money on a PSU. You're paying $350 for an i7 and $600 for a GTX 980TI, yet you won't pay more than $75 for a Corsair CX750. I mean WTF??? Like 99% of the time on this website the answer to most people's problems with their system is "buy a new PSU". And it is really sad when people don't see that's a huge investment.


    Especially when a 750 watt EVGA B2 is like $55

    Quote:
    I have both 850W and 750W versions of the G2 and I've never seen an issue with either one in regards to noise.


    Well... it's a matter of perspective. If you have two Gigabyte G1's, twin CPU fans, and say 6 case fans, you're not going to hear the PSU fan ... but if you invested a boatload of money in water cooling components, the radiator fans are spinning at 350 - 500 rpm under normal usage. The noise associated with that is below the audible range of hearing. To have that peace and quiet disturbed and your investment negated by the lack of a quiet PSU fan is disheartening.
  • turkey3_scratch
    It's about time we get a white PSU.
  • JackNaylorPE
    Well there was this .... and it was $180 five years ago.

    NZXT Hale90 850W (9.5 performance / 10.0 build quality)
    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=199

    This is better and cheaper considering inflation.
  • DookieDraws
    That sure is one sexy PSU! I have the Seasonic 660W Platinum PSU, but I might haver to kick her to the curb for this fine young lady. I can just see her sitting inside my Enthoo Pro, now. That big window on the side of my Enthoo Pro would show her off real nicely. :P

    Nice job, Seasonic!