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Seasonic X-Series XM2-1250 Power Supply Review

Manufacturer: Seasonic

Introduction and Features

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Seasonic is a well known and highly respected OEM that produces some of the best PC power supplies on the market today. In addition to supplying power supplies to many big-name companies who re-brand the units with their own name, Seasonic also sells a full line of power supplies under the Seasonic name. The new XM2-1250 is the latest addition to the X-Series and features an improved Hybrid Fan control circuit and upgraded copper conduction bars on the main PCB, which together increase efficiency and performance.

The new XM2-1250 is a second generation X-Series power supply that comes with fully modular cables and a 120mm Sanyo Denki cooling fan. It is designed to provide ultra-tight voltage regulation along with high efficiency (80 Plus Gold certified).

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Seasonic X-Series XM2-1250 Special Features

Ultra Tight Voltage Regulation Improved load voltage regulation keeps the voltage fluctuations on the 12V output within +2% and -0% (no negative tolerance), and on the 3.3V and 5V outputs between +1% and -1%, which (under 80 Plus load conditions) results in smooth and stable operation.

Seasonic Hybrid Silent Fan Control The industry first, advanced three-phased thermal control balances between silence and cooling. The Hybrid Silent Fan Control provides three operational stages: Fanless, Silent and Cooling Mode.  In addition, a selector switch is provided to allow for manual selection between the Seasonic S2FC (fan control without Fanless Mode) or S3FC (fan control including Fanless Mode).

Reduced Cooling Fan Hysteresis is achieved by a new fan control IC, which optimizes how frequently the fan switches on and off. At 25°C ambient temperature the fan turns on when the load rises above 30% (±5%) and turns off when the load drops below 20% % (±5%). Due to this lag in response the fan switches on and off less frequently, which reduces power loss in Fanless and Silent Mode.

Dual Copper Conduction Bars on the power supply PCB help reduce impedance and minimize voltage drop, which further improves efficiency and performance.

80Plus Gold The XM2-1250 power supply is certified in accordance to the 80PLUS organization's Gold standards, offering performance and energy savings with up to =90% efficiency and a true power factor of greater than 0.9 PF.

Full Modular Design (DC to DC) The Seasonic X-Series power supplies feature an integrated DC connector panel with onboard VRM (Voltage Regulator Module) that enables not only near perfect DC-to-DC conversion with reduction of current loss/impedance and increase of efficiency but also a fully modular DC cabling that enables maximum flexibility of integration and forward compatibility.

Seasonic XM2-1250 PSU Key Features:

•    High efficiency, 80Plus Gold certified
•    7-Year manufacturer's warranty worldwide
•    Fully Modular Cable design with flat ribbon-style cables
•    Seasonic DC Connector Panel with integrated VRMs
•    Hybrid Silent Fan Control (3 modes of operation: Fanless, Silent and Cooling)
•    High-quality Sanyo Denki San Ace dual ball bearing fan with PWM
•    Ultra-tight voltage regulation (+2% and -0% +12V rail)
•    Dual copper conduction bars on PCB for improved efficiency and performance
•    Supports multi-GPU technologies
•    Conductive polymer aluminum solid capacitors
•    High reliability 105°C Japanese made electrolytic capacitors
•    ErP Lot 6 2013 compliant and Intel Haswell processor ready
•    PCI-E 8/6 pin x 10, EPS12V/ATX12V x 2, SATA x 14, 4-pin Molex x 5, FDD x 1
•    High current Gold plated terminals with Easy Swap connectors
•    Active PFC (0.99 PF typical) with Universal AC input

Please continue reading our Seasonic XM2-1250 power supply review!

PSU Testing Methodology

Establishing an accurate load is critical to testing and evaluating a PC power supply.  PCPerspective’s power supply test bench can place a precise DC load on the PSU under test.  Each power supply is tested under controlled, real-world conditions up to its maximum rated load (at 40ºC), using both 115 VAC and 240 VAC line voltage.  Our current suite of tests includes:

•    DC Load Regulation
•    AC Ripple and Noise
•    Efficiency
•    Differential Temperature
•    Noise

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The Seasonic X-Series XM2-1250 power supply was evaluated on both features and performance.  A full range of equipment was used to test the power supply under controlled load conditions.  

•    (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
•    (4) CSI3711A Programmable DC load (+12V)
•    (3) 218W Precision resistor load bank (+12V)
•    Switchable precision resistor load bank (-12V and +5VSB)
•    Agilent 34401A digital multimeter (Accuracy ±0.0035% vDC)
•    Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
•    DS1M12 "StingRay" digital oscilloscope (20M S/s with 12 Bit ADC)
•    Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC
•    Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)

The following cables/connectors were used to connect the XM2-1250 to the PCPerspective power supply test equipment.
•    (1) 20+4 pin ATX
•    (1) 4+4 pin EPS/ATX12V
•    (1) 8 pin EPS12V
•    (10) 6-pin PCI-E
•    (2) SATA
•    (2) Molex

July 30, 2014 | 09:55 AM - Posted by willmore (not verified)

Wonderful review, thank you.

July 30, 2014 | 01:16 PM - Posted by Anonymous (not verified)

Can the Corsair individually sleeved cables be used with this unit?

July 30, 2014 | 02:36 PM - Posted by alamakluke

I love my Seasonic X-1250M PSU. I've had it for over 1 year and never had any issues with it. This unit looks even better then the original one.

August 3, 2014 | 08:15 AM - Posted by QD (not verified)

I've had Seasonics go cradle to grave with a couple of PCs- nice PSU.
With this you're looking at a dedicated 15A outlet. Much more and you'll need a 20A.
I think I'll lose interest at 3-phase 208.

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