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Seasonic Prime 850 W Titanium PSU Review

Seasonic made an impressive entry in the 80 PLUS Titanium category with its Prime series. This line's current flagship, offering 850W capacity, is being reviewed today. Besides high efficiency, it sports quiet operation and top performance.

Load Regulation, Hold-Up Time, And Inrush Current

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

Hold-Up Time

Our hold-up time tests are described in detail here.

The 850W model's hold-up time is lower than Seasonic's Prime 650 W, but it still smokes the competition.

Inrush Current

For details on our inrush current testing, please click here.

The inrush current with 115V input is normal. But it's a little higher than expected with 230V.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 to 110 percent of the maximum load the supply can handle, in increments of 10 percentage points.

We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails. 

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedFan NoiseTemps (In/Out)PF/AC Volts
15.206A1.985A1.974A0.995A84.7392.18%440 RPM20.7 dB(A)38.67°C0.968
211.444A2.970A2.961A1.200A169.6193.87%440 RPM20.7 dB(A)38.86°C0.991
318.043A3.478A3.472A1.400A254.8194.12%440 RPM20.7 dB(A)39.48°C0.996
424.629A3.974A3.954A1.605A339.7093.67%440 RPM20.7 dB(A)40.60°C0.993
530.874A4.969A4.946A1.805A424.6293.29%450 RPM21.0 dB(A)41.37°C0.992
637.126A5.961A5.939A2.009A509.5892.71%530 RPM23.6 dB(A)42.15°C0.994
743.380A6.959A6.931A2.214A594.5192.18%410 RPM19.5 dB(A)43.00°C0.995
849.638A7.949A7.922A2.420A679.4891.49%520 RPM23.4 dB(A)44.40°C0.996
956.324A8.455A8.440A2.420A764.5790.76%620 RPM27.6 dB(A)45.44°C0.997
1062.760A8.957A8.927A3.042A849.3090.08%975 RPM37.9 dB(A)46.64°C0.997
1169.828A8.965A8.934A3.049A934.3389.31%1305 RPM47.6 dB(A)46.84°C0.997
CL10.098A12.011A12.005A0.004A102.8489.58%440 RPM20.7 dB(A)45.28°C0.980
CL269.946A1.003A1.003A1.001A859.4390.33%975 RPM37.9 dB(A)46.44°C0.997

Load regulation is tight on all major rails, just like Seasonic promises. In addition, the output noise stays low despite the tough conditions we test under. It's only during the overload test, when we push the PSU beyond its official specs, that the noise reaches 48 dB(A).

Under 10% and 20% loads, this PSU easily meets the corresponding 80 PLUS Titanium levels. Although that's not the case with 50% load, we should stress that our tests are more taxing than the 80 PLUS organization's. Finally, under full load and despite the almost 47°C operating environment, Seasonic's SSR-850TD passes the 90% mark. It is also worth mentioning that the 94% efficiency level is met during the 30% load test. This is one of the most efficient PSUs we have evaluated so far.

Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • 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
    18846027 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 :)