Specifications

Seasonic X-750 Features & Specs
Max. DC Output750W
PFCActive PFC
Efficiency80 PLUS Gold
Operating temperature0°C - 50°C
ProtectionsOver Voltage Protection
Under Voltage Protection
Over Current Protection
Over Power Protection
Over Temperature Protection
Short Circuit Protection
Cooling120 mm Double Ball-Bearing Fan
Dimensions150 mm (W) x 86 mm (H) x 160 mm (D)
Weight2.1 kg
ComplianceATX12V v2.31, EPS 2.92
Warranty7 years
Price at time of review (exc. VAT)＄139.99





Seasonic X-750 Power Specs
Rail3.3V5V12V5VSB-12V
Max. Power25A25A62A3A0.5A
125W744W15W6W
Total Max. Power750W


Cables & Connectors, Power Distribution

Modular Cables
ATX connector (600mm)20+4 pin
8 pin EPS12V (650mm)1
4+4 pin EPS12V (650mm)1
6+2 pin PCIe (560mm+100mm)4
SATA (390mm+120mm+120mm+120mm)8
SATA (300mm+120mm)2
4 pin Molex (500mm+120mm+120mm)3
4 pin Molex (300mm+120mm)2
FDD Adapter (+100mm)1


Packaging





































Contents
















Exterior








































A Look Inside & Component Analysis


















































































Primary Rails Voltage Regulation





















Hold-up Time







Inrush Current



Voltage Regulation and Efficiency Measurements



Voltage Regulation & Efficiency Testing Data 
Seasonic X-750
Test12 V5 V3.3 V5VSBPower
(DC/AC)		EfficiencyFan SpeedFan NoiseTemp
(In/Out)		PF/AC 
Volts
20% Load10.567A1.981A1.969A0.981A149.72W91.99%0 RPM0 dBA48.25°C0.911
12.128V5.039V3.345V5.096V162.76W39.65°C230.0V
40% Load21.514A3.968A3.948A1.180A299.65W93.29%0 RPM0 dBA50.83°C0.961
12.108V5.034V3.341V5.078V321.20W41.50°C229.9V
50% Load26.883A4.962A4.938A1.579A374.62W93.07%957 RPM37.8 dBA40.09°C0.971
12.096V5.031V3.339V5.061V402.50W46.90°C229.9V
60% Load32.250A5.958A5.929A1.980A449.52W92.87%1446 RPM45.4 dBA41.20°C0.977
12.086V5.029V3.338V5.045V484.01W48.24°C229.9V
80% Load43.192A7.954A7.918A2.388A599.44W92.29%1774 RPM50.9 dBA42.11°C0.982
12.065V5.023V3.333V5.020V649.55W50.42°C229.8V
100% Load54.767A8.961A8.914A3.004A749.20W91.48%1808 RPM51.3 dBA44.20°C0.985
12.043V5.019V3.329V4.991V819.00W54.29°C229.7V
110% Load61.015A8.965A8.922A3.005A823.96W90.91%1828 RPM51.5 dBA45.32°C0.985
12.035V5.017V3.328V4.984V906.35W57.31°C229.8V
Crossload 11.963A15.004A15.005A0.502A151.83W86.45%1503 RPM46.5 dBA42.86°C0.921
12.113V5.027V3.337V5.092V175.63W48.50°C230.1V
Crossload 261.950A1.000A1.003A1.002A759.87W92.00%1814 RPM51.3 dBA44.24°C0.985
12.049V5.025V3.337V5.051V825.95W55.40°C229.8V




Efficiency









Efficiency at Low Loads


Efficiency at Low Loads 
Seasonic X-750
Test #12 V5 V3.3 V5 VSBPower
(DC/AC)		EfficiencyFan SpeedFan NoisePF/AC 
Volts
11.827A1.980A1.969A0.195A39.75W82.57%0 RPM0 dBA0.728
12.138V5.042V3.348V5.124V48.14W230.0V
23.393A1.981A1.969A0.389A59.75W86.73%0 RPM0 dBA0.789
12.137V5.042V3.348V5.118V68.89W230.0V
34.961A1.980A1.969A0.586A79.77W88.89%0 RPM0 dBA0.832
12.135V5.041V3.347V5.112V89.74W229.9V
46.526A1.981A1.969A0.779A99.73W90.18%0 RPM0 dBA0.861
12.133V5.040V3.347V5.105V110.59W229.9V



5VSB Efficiency



5VSB Efficiency
Seasonic X-750
Test #5VSBPower (DC/AC)EfficiencyPF/AC Volts
10.102A0.52W69.33%0.043
5.134V0.75W230.3V
20.252A1.29W76.79%0.094
5.131V1.68W230.3V
31.002A5.12W80.13%0.261
5.112V6.39W230.4V
43.002A15.21W81.64%0.384
5.065V18.63W230.2V



Power Consumption in Idle & Standby


Idle / Standby 
Seasonic X-750
Mode12 V5 V3.3 V5VSBPower (AC)PF/AC Volts
Idle12.146V5.044V3.351V5.137V5.55W0.247
230.3V
Standby0.20W0.012
230.3V



Fan RPM, Delta Temperature and Output Noise







+12V Voltage Regulation Chart




5V Voltage Regulation Chart





3.3V Voltage Regulation Chart



Efficiency Chart




+12V Ripple Chart




5V Ripple Chart




3.3V Ripple Chart





5VSB Ripple Chart





Advanced Transient Response Tests


Advanced Transient Response 20%
VoltageBeforeAfterChangePass/Fail
12 V12.125V12.047V0.64%Pass
5 V5.038V4.970V1.35%Pass
3.3 V3.346V3.235V3.32%Pass
5VSB5.098V5.064V0.67%Pass

















Advanced Transient Response 50%
VoltageBeforeAfterChangePass/Fail
12 V12.094V12.016V0.64%Pass
5 V5.030V4.958V1.43%Pass
3.3 V3.340V3.225V3.44%Pass
5VSB5.063V5.028V0.69%Pass




Transient Response at 20% Load













Transient Response at 50% Load















Turn-On Transient Tests










Ripple Measurements



Ripple Measurements
Seasonic X-750
Test12 V5 V3.3 V5VSBPass/Fail
20% Load23.9 mV13.0 mV11.5 mV4.4 mVPass
40% Load29.3 mV13.1 mV12.2 mV5.6 mVPass
50% Load28.9 mV13.2 mV12.3 mV6.3 mVPass
60% Load30.4 mV13.3 mV12.3 mV6.6 mVPass
80% Load34.3 mV14.6 mV12.9 mV7.3 mVPass
100% Load39.0 mV16.6 mV14.1 mV8.6 mVPass
110% Load42.3 mV18.0 mV14.2 mV9.3 mVPass
Crossload 125.1 mV15.2 mV13.5 mV22.4 mVPass
Crossload 238.8 mV14.2 mV13.1 mV23.4 mVPass



Ripple at Full Load














Ripple at 110% Load














Ripple at Crossload 1












Ripple at Crossload 2
















Performance Rating




Performance per Dollar




Value and Conclusion


  • The Seasonic X-750 retails for ＄139.99
  • Delivered full power at 45°C
  • Good ripple suppression
  • Higly efficient
  • Tight voltage regulation
  • Nice price/performance ratio
  • Fully modular
  • Nippon Chemi-Con electrolytic caps
  • Semi-fanless (hybrid) operation
  • Seven-year warranty
  • The fan operation control switch should be at the front of the PSU
9.3Seasonic's technicians had a very difficult task to complete, which was to further improve an already excellent platform. Taking into account the results I obtained by putting together this review and the results of other PSUs that utilize the new platform (Corsair AX860 and AX760), I can easily state that the new platform is significantly more efficient than the older one, and especially at lower loads does it provide tighter voltage regulation and generally higher performance. I think that designs like this one push the conventional methods based on analog circuits to their limits. Only digital control can possibly offer noticeably better results at increased cost; that is, for the time being. Seasonic has a winner in their hands with their fresh KM3 platform, and I can safely assume that they will easily lead the performance race. The new X-750 is Gold certified, but it offer efficiency that many Platinum certified units will envy given it provides super stable and ultra clean DC outputs. It can also operate in fanless mode most of the time because of its cold operation and hybrid fan-control system and has a fully modular design, which increases its usability greatly. The most important facet of all is the price at which Seasonic offers their new X-750; it is, to say the least, decent and fully justified because of the X-750's performance, its features and the long warranty that backs it up. 

To sum up, the X-750's high price/performance ratio renders it a no-brainer in its category, especially if you don't want to spend more money* on a Platinum Corsair/Seasonic unit. 

* After the review was posted, Seasonic informed us that the price of this unit will be increased by ten bucks, reaching ＄149.99 on the 1/1/2013. Unfortunately, some retailers already increased the price of the unit before the end of 2012.