Seasonic Prime 850 W Titanium PSU Review

Protection Features

Check out our PSUs 101 article to learn more about PSU protection features.  

Our protection features evaluation methodology is described in detail here.

Protection Features
OCP12V: -
5V: 28.1A (140.5%)
3.3V: 27.3A (136.5%)
5VSB: 4.1A (136.7%), 79.86mV Ripple
OPP1178.81W (138.7%)
OTPYes (>130°C secondary heat sink)
SCP12V: Yes
5V: Yes
3.3V: Yes
5VSB: Yes
-12V: Yes
PWR_OKProper operation
NLOYes
SIPSurge: MOV
Inrush: NTC thermistor & bypass relay

OCP's triggering points are quite high on the minor rails, though this won't create any trouble since load regulation and ripple suppression are kept under control. However, at 5VSB, ripple with 4.1A is higher than the specification allows, while with only 0.1A lower load it's normal again. Seasonic should look into this and fix it. Lastly, the OPP is set really high. Then again, the PSU doesn't have any problems under almost 1.2kW of load (at normal ambient temperatures, at least).

The other protection features operate properly. OTP is notably present and configured at an optimal level, allowing the PSU to run even under 50°C temperatures per the ATX specification's recommendation.

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16 comments
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  • trampus123
    I want one
  • Nintendork
    There's no need for CF/SLI anymore, the typical PC + RX480/1080 class gpu barely goes above 300w (even less with APU setups or RX460/1050ti). We need way more 400-500w Titanium PSU's.

    We should have 90% efficiency at 50w load with PSU's in that wattage range.
  • WFang
    I'm eagerly anticipating the 600W Passive Seasonic Titanium unit.. I read about it almost a year ago, and still have not seen it tested here ... hope that changes soon.
  • LordDrk
    Paid $179 for my EVGA 1000W T2 on ebay =p
  • mlga91
    Im not worthy of this one.
  • Unolocogringo
    205977 said:
    There's no need for CF/SLI anymore, the typical PC + RX480/1080 class gpu barely goes above 300w (even less with APU setups or RX460/1050ti). We need way more 400-500w Titanium PSU's. We should have 90% efficiency at 50w load with PSU's in that wattage range.


    Just because you do not need one , does not mean others don't.

    I run multiple graphics cards for Folding@Home.The more you can run on each CPU the better. People who run Dual 1080s or dual 39x cards need them to push their 4K monitors.
    So there is a need for them.
  • TJ Hooker
    Nintendork said:
    We need way more 400-500w Titanium PSU's. We should have 90% efficiency at 50w load with PSU's in that wattage range.

    The thing is, efficiency arguably matters less the lower the power is, because the absolute power being wasted is small. A 500W titanium PSU at max load is only drawing 15W more than a gold rated one. At 50%, 10W. As load drops past 50%, efficiency goes down, but absolute power wasted will still likely go down as well. I don't know, getting a 400W titanium PSU just seems like you're probably paying a lot more money than is necessary for a over engineered PSU which has little to no difference in performance compared to a less efficient, cheaper PSU.
  • JV_
    No recommendation award for this one?
  • powernod
    Just like Aris stated at his review, i find it amazing how Seasonic managed to generate such a low ripple values without using cable-in capacitors like the rest of the companies do !!
  • Aris_Mp
    it has an editor's choice. It will be soon added :)
  • bit_user
    1636679 said:
    The thing is, efficiency arguably matters less the lower the power is, because the absolute power being wasted is small.
    I have a 130 W CPU and a 275 W graphics card that spend most of their time idling. I need a pretty big PSU for when they're being stressed, but I want efficiency for the 99% of the time my system spends at 10-20% load.
  • TJ Hooker
    @bit_user I understand where you're coming from, but like I said, even though wasted power as a percentage may be relatively high at low loads, in absolute terms it's quite low. Like 10W from my previous example. That's going to have virtually zero effect on your power bill, and negligible effect on PSU operation. If you're the kind of person who values efficient operation on principle, I get that, I just don't think it's really justified from a practical perspective.
  • bit_user
    1636679 said:
    @bit_user I understand where you're coming from, but like I said, even though wasted power as a percentage may be relatively high at low loads, in absolute terms it's quite low. Like 10W from my previous example.
    Yes, 10W seems like a reasonable ballpark. My power costs me about $0.50 / kWh. If I leave that PC on 24/7, that's almost $4/month. And let's not forget that this is plugged into my UPS, which has its own inefficiencies. And, in the summer, I have to pay again, in order to remove the waste heat from that room via A/C or fans. But I don't pay for heat (it's included in my rent), so it doesn't help during the winter.

    My PC probably idles somewhere in the neighborhood of 85 W, while its current PSU is 860 W (yeah, a little bit overkill). So, about 10%. But 80 Plus only specifies efficiency for 10% load for the Titanium level, so it could be worse than 80% efficiency @ 10% load.

    Now, it so happens that PSU is a Seasonic Platinum model, and I'm definitely not replacing it just for the added efficiency of Titanium. However, if I were buying a new PSU, I'd tend to go for titanium unless doing so involved a tradeoff vs. performance or a significant price difference.

    TBH, I don't leave that PC on 24/7, but it does sometimes stay on (and not sleeping) for days at a time.
  • TJ Hooker
    328798 said:
    1636679 said:
    @bit_user I understand where you're coming from, but like I said, even though wasted power as a percentage may be relatively high at low loads, in absolute terms it's quite low. Like 10W from my previous example.
    Yes, 10W seems like a reasonable ballpark. My power costs me about $0.50 / kWh. If I leave that PC on 24/7, that's almost $4/month. And let's not forget that this is plugged into my UPS, which has its own inefficiencies. And, in the summer, I have to pay again, in order to remove the waste heat from that room via A/C or fans. But I don't pay for heat (it's included in my rent), so it doesn't help during the winter.

    I don't know what average electricity rates are around the world, but considering it's only $0.05-0.08/kWh where I live, it seems like $0.50/kWh is towards the higher end. So with those rates and leaving your PC on 24/7, that's close to a worst case scenario, and it would still likely take months to recoup the extra cost of a titanium PSU. And of course a PC can always be turned off/asleep when not in use, which would significantly lengthen the amount of time necessary to recoup your money.

    Don't know what kind of efficiency your UPS has, but unless it's heinously inefficient it should't be more than a few watts of loss on a 10W load. Cost of removing 10W via A/C should be trivial. There are numerous devices within a home using orders of magnitude more power. Even a human's basal metabolic rate is far higher than that, so just having someone just sitting in the same room is enough to make a 10W load relatively insignificant.

    You're right though, in the case of this Seasonic, you're not just paying for increased efficiency, you're also paying for a top notch platform. But I'm not arguing against this Seasonic. I'm arguing against the importance of ultra-efficient low wattage PSUs in general, especially because efficiency and overall PSU quality aren't necessarily linked.
  • bit_user
    1636679 said:
    I don't know what average electricity rates are around the world, but considering it's only $0.05-0.08/kWh where I live, it seems like $0.50/kWh is towards the higher end.
    My bad. It's closer to $0.20.
  • bissag
    Can the high Inrush current cause damage to components?