Seasonic PRIME 1200 Platinum Power Supply

REVIEW INFORMATION
SUPPLIED BY: Seasonic USA
MANUFACTURER: Seasonic
PRODUCT: PRIME 1200 Platinum
PROD LINK: PRIME Platinum Product Page
PRICE: $229.90 @ Amazon
Price is at the time of testing!

Time for some load testing. We have some high expectations today, and to see if this unit meets them we’ll use the FastAuto load tester, Extech DMM, Tek scope, Rek power meter, and dual probe thermometer to see how this unit performs.

Let’s get going.

PRIME 1200 Platinum – STANDBY Load Tests
Test # +5VSB DC Watts/
AC Watts
Eff. P.F.
Load Tests
1 0.5A 2.48W/
2.92W
84.9% 0.253
4.96V
2 1.5A 7.34W/
9.12W
80.4% 0.449
4.89V
3 3.0A 14.4W/
18.3W
78.7% 0.528
4.80V

The standby results look good. We’ve got 3.2% voltage regulation on this rail, which is an average number, but the mythic performance promised on the box is not what I go looking for in these tests. Anything running in spec here is doing well enough for our needs.

Efficiency ranges from way above average to above average, so Seasonic’s already bringing home the bacon in that regard.

Main test time.

PRIME 1200 Platinum – Cold Load Tests
Test # +3.3V +5V +12V DC Watts/
AC Watts
AC
Input
Eff. P.F. Intake/
Exhaust
Progressive Load Tests
1 1A 1A 8.9A 120.9W/
139.2W
117.1V 86.9% 0.982 27°C/
31°C*
3.307V 4.99V 12.11V
2 1.5A 1.5A 19A 249.7W/
274.0W
117.1V 91.1% 0.986 28°C/
31°C*
3.308V 4.99V 12.10V
3 3.5A 3.5A 47A 607.5W/
661.1W
116.1V 91.9% 0.996 28°C/
45°C
3.305V 4.99V 12.10V
4 5A 5A 70A 900.0W/
992.9W
115.1V 90.6% 0.997 29°C/
49°C
3.300V 4.98V 12.09V
5 7A 7A 93.5A 1204.6W/
1355W
114.2V 88.9% 0.998 31°C/
49°C
3.296V 4.98V 12.08V
Crossload Tests
CL1 15A 15A 0A 129.0W/
154.7W
117.6V 83.4% 0.985 28°C/
39°C
3.298V 4.98V 12.11V
CL2 0A 0A 100A 1212.9W/
1363W
114.5V 89.0% 0.998 29°C/
48°C
3.309V 5.00V 12.08V

* Fanless operation.

It’s a Seasonic… of course, it regulates like a mofo. They’re still killing it, there, with 0.36%, 0.20%, and 0.25% load regulation going from left to right in the above table. Yes, Seasonic just showed up Cooler Master’s fancy Made in Japan 1200W unit for averaging 0.27% regulation at roughly a quarter the price.

Efficiency was a bit of a stretch for Platinum, but with only test three struggling to hit the mark and only by 0.1% I have to give them the pass, there.

Now… the fan. Is loud. Is very loud. It’s not as loud as recent Enhance builds I’ve looked at, like the Thermaltake TPG RGB DPS Titanium 1kW unit, but it’s close. Clearly, the platform is being pushed hard to get this power level out of it, and I have doubts it could be scaled up any further. Not that Seasonic has ever really tried to go higher. Fortunately, it takes full power to get that kind of noise from it, and the fan did stay off until test three.

Let’s turn the page and see if they’ve tackled the S&C point. You’ll remember that the behavior of the Titanium units is what prompted me to start scoring on that part of things.