Corsair RM750 Power Supply Review: Affordable Yet Powerful

Corsair RM750 Power Supply.Corsair RM750 Power Supply.

The Corsair RM750 is the middle member of the new RM line, offering great overall performance and silent operation. It has a street price of $119.99 (£94.2) which is quite high given that the RM750x, featuring better filtering capacitors and a more top quality fan, only costs a few dollars/pounds more. The Seasonic Focus Plus 750W is more affordable than the RM750 and it also comes with Japanese caps; however the latter features much quieter operation.

We have already evaluated the RM850, and we found it to be a good product. The RM750 has 100W less capacity, and like its big brother, it uses Chinese Elite caps and a Hong Hua rifle bearing fan. The slightly more expensive RM750x comes with Japanese caps and the high-quality NR135L fan. Although those differences are notable, still the provided warranty is the same, at ten years, for both models.

 

The RM750 might lose some points compared to the RM750x when it comes to build quality, but it has some aces up its sleeve. Those include increased efficiency under light loads (2% of the max-rated-output) and support for the new Modern Standby mode that the Windows 10 OS introduced. Usually, the S3 sleep state needs 7-15 seconds to turn on, depending on the system, while the Modern Standby function can do this in under five seconds.

The Corsair RM750 is a fully modular power supply, but it doesn't have in-cable caps for some extra ripple filtering. Apparently, Corsair thought that the ripple suppression of this platform is good enough and doesn't need any enhancements. Like in every new power supply, there is a semi-passive operation which cannot be deactivated, unfortunately. Every PSU that can operate in passive mode under light loads, should provide the option for normal operation, in case it is installed with its fan facing downwards.

Specifications

Manufacturer (OEM)CWT
Max. DC Output750W
Efficiency80 PLUS Gold, ETA-A (88-91%)
NoiseLAMBDA-A (20-25 dB[A])
Modular✓ (Fully)
Intel C6/C7 Power State Support
Operating Temperature (Continuous Full Load)0 - 50°C
Over Voltage Protection
Under Voltage Protection
Over Power Protection
Over Current (+12V) Protection
Over Temperature Protection
Short Circuit Protection
Surge Protection
Inrush Current Protection
Fan Failure Protection
No Load Operation
Cooling140mm Rifle Bearing Fan (HA1425M12F-Z)
Semi-Passive Operation
Dimensions (W x H x D) 152 x 87 x 162mm
Weight1.61 kg (3.55 lb)
Form FactorATX12V v2.4, EPS 2.92
Warranty10 Years

Power Specifications

Rail3.3V5V12V5VSB-12V
Max. PowerAmps202062.530.3
Watts150750153.6
Total Max. Power (W)750

Cables & Connectors

Modular Cables
DescriptionCable CountConnector Count (Total)GaugeIn Cable Capacitors
ATX connector 20+4 pin (610mm)1118-20AWGNo
4+4 pin EPS12V (650mm)2218AWGNo
6+2 pin PCIe (600mm+150mm) 3616-18AWGNo
SATA (450mm+110mm+110mm+110mm)1318AWGNo
SATA (500mm+100mm+100mm)2618AWGNo
4 pin Molex (450mm+100mm+100mm+100mm)1418AWGNo
AC Power Cord (1420mm) - C13 coupler1116AWG-

There are two EPS and six PCIe connectors, which are more than enough for a 750W power supply. The number of the peripheral connectors is sufficient, but the distance between them is small at 100mm. Ideally, it should be 150mm.

Component Analysis

We strongly encourage you to have a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss.

General Data
 Corsair RM750 (2019)Corsair RM750x (2018)
Manufacturer (OEM)CWTCWT
PCB TypeDouble SidedDouble Sided
Primary Side
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV4x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Inrush ProtectionNTC Thermistor & RelayNTC Thermistor & Relay
Bridge Rectifier(s)2x GBU1506 (600V, 15A @ 100°C)2x GBU1506 (600V, 15A @ 100°C)
APFC MOSFETS2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ohm)1x Power Integrations QH08TZ600 (600V, 8A @ 150°C)
APFC Boost Diode1x Power Integrations QH08TZ600 (600V, 8A @ 95°C)1x Power Integrations QH08TZ600 (600V, 8A @ 150°C)
Hold-up Cap(s)2x Su'scon (400V, 330uF each or 660uF combined, 2,000h @ 105°C, LZ)2x Nichicon (400V, 1x 470uF, 1x 390uF, 2000h @ 105°C, GG)
Main Switchers2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ohm)2x Infineon IPA60R190P6  (650V, 12.7A @ 100°C, 0.190 Ohm)
APFC ControllerChampion CM6500UNX & CM03X Green PFC ControllerChampion CM6500UNX
Resonant ControllersChampion CU6901VChampion CM6901X
TopologyPrimary side: Half-Bridge & LLC converter
Secondary side: Synchronous Rectification & DC-DC converters
Primary side: Half-Bridge & LLC Resonant Controller
Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETS6x International Rectifier IRFH7004PBF (40V, 100A @ 25°C, 1.4mOhm)6x International Rectifier IRFH7004TRPBF (40V, 164A @ 100°C, 1.4 mOhm)
5V & 3.3VDC-DC Converters: 2x UBIQ QM3054M6 (30V, 61A @ 100°C, 4.8mOhm) & 2x UBIQ QN3107M6N (30V, 70A @ 100°C, 2.6mOhm)
PWM Controllers: uPI SEMI uP3861P
DC-DC Converters: 6x QM3006D (30V, 57A @ 100°C, 5.5 mOhm)
PWM Controller: ANPEC APW7159
Filtering CapacitorsElectrolytics: 7x Elite (2-5,000h @ 105°C, EK), 1x Elite (4-10,000h @ 105°C, EY), 1x Elite (2,000h @ 105°C, PF), 2x Su'scon (2-5,000h @ 105°C, MF), 3x Su'scon (4-10,000h @ 105°C, HG)
Polymers: Suncon, Elite, NIC
Electrolytics: Nippon Chemi-Con (1-5,000 @ 105°C, KZE), Nippon Chemi-Con (4-10,000 @ 105°C, KY)
Polymers: FPCAP
Supervisor ICWeltrend WT7502 (OVP, UVP, SCP, PG) & LM393GWeltrend WT7502 (OVP, UVP, SCP, PG) & LM393G
Fan ControllerMicrochip PIC16F1503PIC16F1503
Fan ModelHong Hua HA1425M12F-Z (140mm, 12V, 0.36A, Rifle Bearing Fan)NR135L (12V, 0.22A, Rifle Bearing)
5VSB Circuit
Rectifier1x Unisonic Technologies 4N65L (650V, 4A @ 25°C, 2.5Ohm)ISD04N65A, QM3004D,  LS64 10L45 SBR
Standby PWM ControllerOn - Bright OB5282On-Bright OB5269CP

The table above shows the part differences in the RM750 and RM750x models. As you can see, CWT used a newer resonant controller which allows for higher efficiency under super-light loads, thanks to the burst mode operation.

The topology on the primary side remains the same, half-bridge which is supported by an LLC resonant converter. On the secondary side, the FETs that regulate the +12V rail are different, and the same goes for the FETs that handle the minor rails.

The soldering quality on the main PCB is good. CWT has good production lines, so we didn't expect anything less here.

We would prefer to see the NR135L fan in the RM units, instead of the 140mm Hong Hua, because the first proved to be bullet-proof so far.

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1 comment
    Your comment
  • DSzymborski
    It's really hard to recommend this at the price. Offer this at $75 and it's interesting, but there's always something better at this price that'll undercut it and a few additional sales that put under this (SeaSonic Focus, EVGA G3, etc). I don't think this is even competitive at $100.