Riotoro Enigma 850W PSU Review

Transient Response Tests

Advanced Transient Response Tests

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

Ιn these tests, we monitor the Enigma 850's response in several scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V, and 0.5A at 5VSB) is applied for 200ms as the PSU works at 20 percent load. In the second scenario, it's hit by the same transient load while operating at 50 percent load.

In the next sets of tests, we increase the transient load on the major rails with a new configuration: 15A at +12V, 6A at 5V, 6A at 3.3V, and 0.5A at 5VSB. We also increase the load-changing repetition rate from 5 Hz (200ms) to 50 Hz (20ms). Again, this runs with the PSU operating at 20 and 50 percent load.

The last tests are even tougher. Although we keep the same loads, the load-changing repetition rate rises to 1 kHz (1ms).

In all of the tests, we use an 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 these "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 – 200ms

VoltageBeforeAfterChangePass/Fail
12V12.094V11.913V1.50%Pass
5V5.071V4.972V1.95%Pass
3.3V3.330V3.207V3.69%Pass
5VSB4.992V4.950V0.84%Pass

Advanced Transient Response at 20 Percent – 20ms

VoltageBeforeAfterChangePass/Fail
12V12.096V11.815V2.32%Pass
5V5.071V4.963V2.13%Pass
3.3V3.331V3.171V4.80%Pass
5VSB4.991V4.944V0.94%Pass

Advanced Transient Response at 20 Percent – 1ms

VoltageBeforeAfterChangePass/Fail
12V12.098V11.935V1.35%Pass
5V5.072V4.965V2.11%Pass
3.3V3.331V3.186V4.35%Pass
5VSB4.990V4.933V1.14%Pass

Advanced Transient Response at 50 Percent – 200ms

VoltageBeforeAfterChangePass/Fail
12V12.051V11.955V0.80%Pass
5V5.039V4.941V1.94%Pass
3.3V3.307V3.187V3.63%Pass
5VSB4.949V4.904V0.91%Pass

Advanced Transient Response at 50 Percent – 20ms

VoltageBeforeAfterChangePass/Fail
12V12.052V11.907V1.20%Pass
5V5.040V4.919V2.40%Pass
3.3V3.308V3.166V4.29%Pass
5VSB4.949V4.900V0.99%Pass

Advanced Transient Response at 50 Percent – 1ms

VoltageBeforeAfterChangePass/Fail
12V12.054V11.911V1.19%Pass
5V5.040V4.932V2.14%Pass
3.3V3.308V3.149V4.81%Pass
5VSB4.947V4.883V1.29%Pass

The Enigma 850W successfully passes all of our transient response tests, though we'd like to see lower deviations on the 3.3V rail.

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

Transient Response At 20 Percent Load – 200ms

Transient Response At 20 Percent Load – 20ms

Transient Response At 20 Percent Load – 1ms

Transient Response At 50 Percent Load – 200ms

Transient Response At 50 Percent Load – 20ms

Transient Response At 50 Percent Load – 1ms

Turn-On Transient Tests

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

For the first measurement, we turned the Enigma 850 off, dialed in the maximum current its 5VSB rail could output, and switched the PSU back on. In the second test, we dialed the maximum load the +12V could handle and started the 850W supply while it was in standby mode. In the last test, while the PSU was completely switched off, we dialed the maximum load the +12V rail could handle before switching it back on 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 5.5 V for 5V). 

Nothing our of the ordinary here.

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16 comments
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  • Pompompaihn
    Enigma is a HORRIBLE name for the one part in your computer you want to always work exactly as specified and never outside of those specs....
  • gdmaclew
    All I want to know is...Tier 1, Tier 2, Tier 3 or Tier 4?
  • zthomas
    850 will power a normal system.. but thinking VR or a second video card.. 850 ain't enough.. I just upgraded from a 700 to a 1200.. why go small, go larger.. you run a 900 series.. you want a punch.. not a lag..
  • maxwellmelon
    A mov can be a blessing and a curse. When the MOV eventually fails it offers no protection (and there is no indicator on it to indicate failure) then after awhile it will form into a short at which point the psu will fail to work due to a short on the incoming mains. so your MOV will can extend the life by protecting the psu. but in the end it will be the end of the psu. In a lot of ways it is still better to get a good surge protector with MOV protection inside of it because they actually have an indicator to let you know the MOV has failed and you can actually replace the surge protector..If the MOV has failed in the psu you will never know and even if you did know the whole PSU has to be replaced. a good surge protector is still cheaper to replace then the psu.
  • anbello262
    1415492 said:
    850 will power a normal system.. but thinking VR or a second video card.. 850 ain't enough.. I just upgraded from a 700 to a 1200.. why go small, go larger.. you run a 900 series.. you want a punch.. not a lag..


    I actually don't agree with you at all. 850w is enough for almost any system with even 1080 SLI, and VR doesn't actually require more power by itself (only requires power by high utilization of your system).
    So for almost anyone, 650w is more than enough even for high end systems, and if you want to SLI high end cards, then 850W is advisable.
    More than that is overkill in almost all cases, in my (somewhat informed) opinion.

    Having a good quality PSU is a lot more important than having more than 850W. And quality PSUs with more power tend to be a lot more expensive than a very good 850w one, from my experience.
  • Aris_Mp
    you are right about the MOV, however personally I prefer a PSU featuring a MOV along with a UPS and a surge arrester combination. Moreover, for users that don't use surge arresters etc a MOV can save their systems besides the PSU and this is why it must be used always.
  • jonnyguru
    141101 said:
    All I want to know is...Tier 1, Tier 2, Tier 3 or Tier 4?


    If that's not a joke, then you sir do not need to be here... let alone building PCs.
  • anbello262
    112719 said:
    141101 said:
    All I want to know is...Tier 1, Tier 2, Tier 3 or Tier 4?
    If that's not a joke, then you sir do not need to be here... let alone building PCs.


    Actually, having the PSUs ordered in quality tiers is a very handy way to recommend PSUs, and therefore, for the people who are not so technically proficient with the electronics inside a PSU and specific meanings of the tests, knowing if this is a "Great, good or garbage" PSU is the only important part.

    Yes, there is more information to be had by reading the whole review, but only for those who understand it (which is by no means necessary, in order to be a very good system builder). Having a qualified person tell you "this is a safe and recommended unit for system builders / this is good enough for the price / don't buy this!" is extremely useful for the whole community.
  • Robert Cook
    If nothing else it is more competition, and a pretty promising start at that.
    A solid review.
    <Rant>
    Now on other news, PLEASE stop those damn auto play videos embedded in articles! My main system might be fine with them, but my laptop is from 2009, and it was not high spec even then. These videos are a major drain, and now there are ads before hand which means I cannot even hit the X option until the ad has played. (So I am loading free ad revenue for you at the cost of my precious little RAM.)

    Annoying clickbait is one thing, I can scroll past it, but these auto play ads/videos follow me down the page... :(

    I have been a member here for over two years and I am by no means going to stop, but I would like to be able to read articles (especially well done articles on this site) with out having great difficulty even scrolling down a page.
    </Rant>
  • Robert Cook
    Also I do not even use adblock so you are already getting ad revenue. (I respect your right to advertise, but force playing a video and then adding ads seems a bit over blown.)
  • zthomas
    1846741 said:
    Also I do not even use adblock so you are already getting ad revenue. (I respect your right to advertise, but force playing a video and then adding ads seems a bit over blown.)


    sounds to me you could use adblock.. its free.. will stop all those annoying adds and popups..
  • Karadjgne
    CS850 is $120, this unit is $110. That's going to be a hard sell when faced by brand recognition. Never heard of the brand, assume it's junk or it would be known, buy what I've heard of. What's going toake it harder is sli builds using high end gpus are expensive, builders will go with a reputable psu, Evga, Seasonic, Corsair for 850w. Doubt someone who can afford twin 1080's will be even tempted to look at this unit. Which leaves the ppl who have 2 hdds so need to have more power and a gtx1060, so 850w just to be safe crowd.
    I think Riotoro should have taken the shorter route, like the CX 430 did, and blown the doors off the 400/450w market at $10 cheaper than the CXM 450
  • WhyAreYou
    Looks nice actually, good review
  • amk-aka-Phantom
    1426528 said:
    I actually don't agree with you at all. 850w is enough for almost any system with even 1080 SLI, and VR doesn't actually require more power by itself (only requires power by high utilization of your system). So for almost anyone, 650w is more than enough even for high end systems, and if you want to SLI high end cards, then 850W is advisable. More than that is overkill in almost all cases, in my (somewhat informed) opinion.


    Agreed completely. I have a single GTX 970 with a Core i7-2600 (still kicking!) and I almost managed to run it off a 400 W Seasonic PSU (I normally use a 750 W that I bought a long time ago planning to SLI two 560 Ti). Almost - because *once* in a while I'd get power-related BSODs in Overwatch. But I bet a 450 W would manage it just fine. People's obsession with higher-wattage PSUs is unjustified, and to those who say "why not" - BUDGET!
  • Karadjgne
    Can't blame ppl for wanting bigger. Yes, you probably could squeeze in a i7-2600 and gtx970 on a 450w, I know it's been done before. But running that close to maximum output by the psu for any length of time does have its own quirks. First, there's no guarantee that any particular buyer is going to get a high quality, tier 1 or tier 2 psu that'll withstand that abuse, many opt for more budget oriented tier 3 mediocre units. So quality power outputs, ripple suppression etc is dubious at best at closer to 100% loads. Second is the best efficiency, power to heat ratios, power cleanliness, fan noise, etc. is found in the 50% to 70% range. This is why any system running a gtx970 should be at a minimum of 520-550w. Third, there are no quality 500,600,700w units. None. For any quality unit you are looking at 450,520,550,620,650,750w units. So again, 520-550w is perfect for a 970. Forth is OC. This varies per user, personally my 3570k is at 4.3GHz and it's gtx660ti is max OC on a Seasonic M12-II 520w. My 3770k is currently at 4.6GHz (was 4.9GHz) and its gtx970 is max OC on a Evga G2 550w. Neither is overkill powered, but both are quality units designed to handle whatever I can throw at them and still come out smiling.

    There's only one hard and fast rule of psus. Don't skimp. Be surprised how many people try and cheat that, only to end up with power related issues.
  • anbello262
    1011591 said:
    First, there's no guarantee that any particular buyer is going to get a high quality, tier 1 or tier 2 psu that'll withstand that abuse


    That's exactly the reason I said that, for a given budget, Quality is a lot more important than Capacity. Usually it's a lot better to have a 550W top quality one for a than a 750W cheap/mediocre one, for example. And almost in every single case where lots of power are necessary, it's better to get a top quality 850W than a mediocre 1200W (as someone above suggested).


    1011591 said:
    There's only one hard and fast rule of psus. Don't skimp. Be surprised how many people try and cheat that, only to end up with power related issues.


    I completely agree with this. It was common that most games will not tax both cpu and gpu to their max power consumption numbers for long periods of time, but that is no longer the case with Overwatch and some other apps, and therefore a lot of people who skimped on their psu are having issues now.

    But I also think that it is quite unwise to go to the other extreme. Buying a 1200W top quality unit when you would only need 750/850W would be an unnecessary waste of money for almost all builders.