Seasonic Platinum-1000 1000 W

Lately more and more OEMs are in a constant race against time to release the best, high wattage, 80 Plus Platinum unit. Some major players, like Enermax and SuperFlower, have already included high wattage Platinum units in their arsenal. Recent reviews were also unable to verify platinum efficiency in many real life scenarios. Achieving platinum efficiency in low capacity units may be a difficult task but doing so in a high capacity unit is much more difficult because as power climbs, energy dissipation increases too and even the smaller resistance in a conductor can lead to significant energy/efficiency losses when lots of current passes through. So Seasonic, even with their huge experience, had to study the Platinum efficiency subject extensively, something that led to their late entry in this club. Of course when you already have a very successful product like the X Series, then future plans are even harder, since you have to release something significantly improved.

Seasonic’s fresh Platinum series includes two units, with 860W and 1000W capacity. Both are fully modular, use only Japanese 105°C capacitors, have a single +12V rail and utilize a hybrid fan control which offers silent operation (more on this feature in the next pages). Today we will have the chance to test the 1000W unit (or SS-1000XP) and see how it scores against the competition.

Specifications

Seasonic SS-1000XP Features & Specs
Max. DC Output	1000W
PFC	Active PFC
Efficiency	80 PLUS Platinum
Operating temperature	0°C - 50°C
Protections	Over Voltage Protection Under Voltage Protection Over Current Protection Over Power Protection Over Temperature Protection Short Circuit Protection
Cooling	120 mm Double Ball-Bearing Fan with Hybrid Silent Fan Control
Dimensions	150 mm (W) x 86 mm (H) x 190 mm (D)
Weight	2.1 kg
Compliance	ATX12V, EPS12V
Warranty	7 years
Price at time of review (exc. VAT)	$259.99

Besides the Platinum efficiency, this unit is equipped with a full set of protections since even the rare OTP (Over Temperature Protection) is included. The cooling fan features double ball bearings for extended lifetime so along with the Japanese capacitors and the seven year warranty you will have an absolute peace of mind. Its length is not small at 190mm but most mid-full towers will accommodate it without any problems. The weight is relatively low since we weighted it without any modular cables attached. On top of that in a platinum efficiency unit the heatsinks are not large since heat dissipation is kept low. Finally, the price Seasonic asks for the SS-1000XP looks a little bit high since the direct competitor, KINGWIN LZP-1000, costs $30 less.

Seasonic SS-1000XP Power Specs
Rail	3.3V	5V	12V	5VSB	-12V
Max. Power	25A	25A	83A	3A	0.5A
Max. Power	125W		996W	15W	6W
Total Max. Power	1000W

There is one, powerful, +12V rail which can deliver the full power of the PSU. The minor rails are kept to only 125W max combined power but a modern system will not ask for more. On the contrary, since we are talking about a 1kW PSU here, we would like to see at least one Ampere more at 5VSB.

Cables & Connectors, Power Distribution

Modular Cables
ATX connector (600mm)	20+4 pin
8 pin EPS12V (650mm)	1
4+4 pin EPS12V/ATX12V (650mm)	1
6+2 pin PCIe (600mm)	6
4 pin Molex (550mm+150mm+150mm)	6
4 pin Molex (350mm+150mm)	2
SATA (540mm+150mm+150mm)	9
SATA (350mm+150mm)	2
FDD Adapter (+150mm)	2

The available connectors are enough for the unit's capacity and their lengths are adequate so you won't meet any problems even in very large tower cases. Also the distance among the connectors is the right one, according to ATX spec.
As you can see in the table above there are six PCIe connectors which in pairs start from a common connector but immediately split into two separate cables. There are also two EPS connectors which can be used at the same time with the six PCIe ones. The EPS and PCIe connectors use thicker, 16AWG, wires while all other connectors, including the 24pin ATX, use 18AWG gauges. We would highly prefer the 24pin ATX to use 16AWG gauges too for smaller impedance, something that would lead to lower voltage drops on the minor rails, especially at high loads.

Since this PSU features a single +12V rail we do not have anything to comment about its power distribution.

Ripple Measurements

In the following table you will find the ripple levels that we measured on the main rails of the SS-1000XP. According to ATX specification the limits are 120 mV (+12V) and 50 mV (5V, 3.3V and 5VSB).

Ripple Measurements Seasonic SS-1000XP
Test	12 V	5 V	3.3 V	5VSB	Pass/Fail
20% Load	23.6 mV	9.7 mV	8.5 mV	17.0 mV	Pass
40% Load	15.5 mV	8.8 mV	9.4 mV	7.7 mV	Pass
50% Load	15.8 mV	11.2 mV	9.6 mV	8.2 mV	Pass
60% Load	16.6 mV	11.4 mV	10.6 mV	10.8 mV	Pass
80% Load	20.1 mV	11.4 mV	11.4 mV	11.9 mV	Pass
100% Load	24.0 mV	12.5 mV	14.9 mV	13.6 mV	Pass
Crossload 1	37.6 mV	9.5 mV	9.7 mV	12.3 mV	Pass
Crossload 2	23.8 mV	11.8 mV	12.2 mV	22.4 mV	Pass

As expected from Seasonic's flagship PSU, ripple/noise suppression is excellent. Even at full load ripple at +12V is at one fifth of the limit. With 20% load, ripple is higher compared to other load levels because at low loads the unit works in PWM mode and only at higher loads it uses FM mode.

Ripple at Full Load

In the following oscilloscope screenshots you can see the AC ripple and noise that the main rails registered (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the oscilloscope's screen the bigger the ripple/noise. For all measurements we set 0.01 V/Div (each vertical division/box equals to 0.01V) as standard.