Seasonic Platinum SS-1050XP3 Cold Test Results

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox, and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

As expected, the Seasonic Platinum SS-1050XP3 delivers excellent energy conversion efficiency at room temperature, reaching an average conversion efficiency within the nominal load range (20% to 100%) of 93.1%. With a conversion efficiency of 94.2% at 50% load, it covers the 80 Plus Platinum requirements, yet the maximum conversion efficiency is 94.3% and appears at 40% load. At just 5% load, the efficiency takes a dive to just 76.1%. While this is natural for a switching PSU, the efficiency climbs at an extraordinary rate, reaching 89.2% at just 10% load. This makes the Seasonic Platinum SS-1050XP3 the first unit that we have seen to date with lower losses after doubling its power output from 53 to 105 Watts.

Despite the very high energy conversion efficiency, it appears that Seasonic designed the Platinum SS-1050XP3 with thermal performance in mind, not silent operation. Even with the fan in hybrid mode and at room temperature, the fan starts at 30% load, while the temperature of the PSU is still relatively low. This has a very positive impact on the thermal performance of the PSU, which maintains a very low operating temperature even at maximum load. On the other hand, the 120mm fan can be clearly heard at just 40% load and its speed climbs rapidly as the load increases, surpassing even 50dB(A) at very high loads. At such noise levels, the Platinum SS-1050XP3 can be clearly heard from rooms away.

The Seasonic Platinum SS-1050XP3 & SS-1200XP3 PSUs Seasonic Platinum SS-1050XP3 Hot Test Results
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  • Impulses - Thursday, September 4, 2014 - link

    I'm not sure I buy that NV and AMD are putting efficiency at the forefront, seems it's kinda cyclical for each ands then they regress.

    Case in point, I recently had to buy a new PSU because the 750W that could easily handle two AMD HD6950 in CFa couple years ago wouldn't be enough for two new R9 290. Ended up with a Seasonic X-1250 just because it was on sale (was looking at 1K units otherwise).

    Seasonic's biggest competition seems to be themselves (they now have three top end lines? the Gold X models and two Platinum lines?) and the various brands that resell Seasonic designs (XFX etc).
  • romrunning - Thursday, September 4, 2014 - link

    I'm curious - how much power does your system actually draw?

    A link here ( said the R9 290 draws 250W. Even if they spike to 275-300W under heavy load, you still have 150W for everything else. Are you running a 220W AMD CPU or something?
  • Impulses - Friday, September 5, 2014 - link

    I could maybe get away with the 750W unit, but I wasn't really looking forward to running it at 100% load thru hours of gaming, and/or unexpected crashes while OC'ing etc.
  • DanNeely - Thursday, September 4, 2014 - link

    There's something wrong with the -12V column in the table. 3A @ -12V would be 36 watts of power not 6. 3A also seems unusually high for a current generation model.
  • E.Fyll - Thursday, September 4, 2014 - link

    Thank you for pointing that out Dan. The 5VSB and -12V columns were reversed, that was a typo mistake on my part.
  • WilbertCane29 - Friday, September 5, 2014 - link

    I found this to be really interesting. Are there any more sources on this? I would like to know more about this.
  • Oxford Guy - Wednesday, December 3, 2014 - link

    Typical review site doublespeak:

    The power supply can be "ear splitting" and "be heard from rooms away" but:

    "we do believe that very few users actually require their system to remain silent while it is heavily loaded."

    Give me a freakin' break. 50+ db is related to a desire for silence how, exactly? Not having something cause someone to develop tinnitus during the warranty period has to do with a quest for silence how, exactly?

    "it is known that such powerful units have a very limited target audience."

    Yes, the deaf.
  • Oxford Guy - Wednesday, December 3, 2014 - link

    It's long past time for these antique standards like ATX with 120mm fans be replaced. If you're going to provide 1000 watts of power or more, move to a new form factor. How about a 200mm fan with a vapor chamber?

    Think outside of the bloody box! And, stop apologizing for these poor thoughtless designs. This power supply is unsuitable for use out side of a server room.
  • Oxford Guy - Wednesday, December 3, 2014 - link

    It pisses me off to no end to see the same regurgitation of anachronism year after year, with the most miniscule changes being hailed as great innovation. Why can't companies actually innovate?

    Make the entire top of a PC case a triple width 360mm radiator instead of these absurd tower designs with redundant narrow radiators and fans splattered all over the place, competing with each other. Link in the GPUs, the CPU, the motherboard VRMs, and the power supply with heat pipes and a giant vapor chamber. Do something instead of this piecemeal and pathetic series of attempts to shoehorn high wattage equipment into form factors that don't work.

    I remember when Apple told people to drop their Apple IIIs onto desks to reseat the chips that popped out from heat — because Apple designed the case to be oh-so-pretty before it finished engineering the internals! This is the same nonsensical mentality that dominates the "enthusiast" equipment industry and review sites' appraisals. The assumption is that the form factors already exist and must be slavishly followed, no matter how idiotic the result.

    But, while I sit around unemployed in disgust in the midst of cornfields I get to see the parade of banality continue...

    I realize that Silverstone has done a bit with its triple and dual 180mm fan rotated designs but those are not adequate for really quiet computing with high wattage multiple GPU machines. People even suggest pairing blower GPUs with those cases. Blower GPUs! Blowers on GPUs should have been consigned to the relic bin 10 years ago. Sure... let's pair a high wattage part with a teeny tiny little fan and form factor. Then, let's put two or three into the system to double or triple the stupidity. That makes sense!

    Linked heat pipes, linked radiators, big vapor chambers, single air path, the case acting as a heat sink as well... Centralized non-redundant non-competitive cooling mechanisms. That is the future, not more of the same 50+ db just for the power supply BS, teeny tiny fans, 5 or 6 airflow paths in different directions, and general anachronistic chaos disguised as cleverness.

    I know it makes more money for manufacturers to keep people in the upgrade mouse wheel, trying to get a decent product by cobbling together all the half-hearted efforts but it's time to start delivering a holistic well-made product without paying Mac Pro prices or worrying about Apple's obsession with glamour.

    Get with it, people.

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