Tom's Hardware Verdict
The RM750 is a good choice for anyone wanting a reliable and silent power supply at a decent price.
Pros
- +
Full power at 47 degrees Celsius
- +
Quiet operation
- +
Supports Modern Standby mode
- +
Efficient under light loads
- +
Ten-year warranty
Cons
- -
Only a little less expensive than the RM750x
- -
No option to deactivate semi-passive operation
- -
The RMx units come with a better fan
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Specifications and Part Analysis
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 Output | 750W |
| Efficiency | 80 PLUS Gold, ETA-A (88-91%) |
| Noise | LAMBDA-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 | ✓ |
| Cooling | 140mm Rifle Bearing Fan (HA1425M12F-Z) |
| Semi-Passive Operation | ✓ |
| Dimensions (W x H x D) | 152 x 87 x 162mm |
| Weight | 1.61 kg (3.55 lb) |
| Form Factor | ATX12V v2.4, EPS 2.92 |
| Warranty | 10 Years |
Power Specifications
| Rail | 3.3V | 5V | 12V | 5VSB | -12V | |
|---|---|---|---|---|---|---|
| Max. Power | Amps | 20 | 20 | 62.5 | 3 | 0.3 |
| Watts | 150 | 750 | 15 | 3.6 | ||
| Total Max. Power (W) | 750 |
Cables & Connectors
| Modular Cables | ||||
|---|---|---|---|---|
| Description | Cable Count | Connector Count (Total) | Gauge | In Cable Capacitors |
| ATX connector 20+4 pin (610mm) | 1 | 1 | 18-20AWG | No |
| 4+4 pin EPS12V (650mm) | 2 | 2 | 18AWG | No |
| 6+2 pin PCIe (600mm+150mm) | 3 | 6 | 16-18AWG | No |
| SATA (450mm+110mm+110mm+110mm) | 1 | 3 | 18AWG | No |
| SATA (500mm+100mm+100mm) | 2 | 6 | 18AWG | No |
| 4 pin Molex (450mm+100mm+100mm+100mm) | 1 | 4 | 18AWG | No |
| AC Power Cord (1420mm) - C13 coupler | 1 | 1 | 16AWG | - |
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 | ||
|---|---|---|
| Row 0 - Cell 0 | Corsair RM750 (2019) | Corsair RM750x (2018) |
| Manufacturer (OEM) | CWT | CWT |
| PCB Type | Double Sided | Double Sided |
| Primary Side | ||
| Transient Filter | 4x Y caps, 2x X caps, 2x CM chokes, 1x MOV | 4x Y caps, 2x X caps, 2x CM chokes, 1x MOV |
| Inrush Protection | NTC Thermistor & Relay | NTC Thermistor & Relay |
| Bridge Rectifier(s) | 2x GBU1506 (600V, 15A @ 100°C) | 2x GBU1506 (600V, 15A @ 100°C) |
| APFC MOSFETS | 2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ohm) | 1x Power Integrations QH08TZ600 (600V, 8A @ 150°C) |
| APFC Boost Diode | 1x 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 Switchers | 2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ohm) | 2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.190 Ohm) |
| APFC Controller | Champion CM6500UNX & CM03X Green PFC Controller | Champion CM6500UNX |
| Resonant Controllers | Champion CU6901V | Champion CM6901X |
| Topology | Primary 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 MOSFETS | 6x International Rectifier IRFH7004PBF (40V, 100A @ 25°C, 1.4mOhm) | 6x International Rectifier IRFH7004TRPBF (40V, 164A @ 100°C, 1.4 mOhm) |
| 5V & 3.3V | DC-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 Capacitors | Electrolytics: 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 IC | Weltrend WT7502 (OVP, UVP, SCP, PG) & LM393G | Weltrend WT7502 (OVP, UVP, SCP, PG) & LM393G |
| Fan Controller | Microchip PIC16F1503 | PIC16F1503 |
| Fan Model | Hong Hua HA1425M12F-Z (140mm, 12V, 0.36A, Rifle Bearing Fan) | NR135L (12V, 0.22A, Rifle Bearing) |
| 5VSB Circuit | ||
| Rectifier | 1x Unisonic Technologies 4N65L (650V, 4A @ 25°C, 2.5Ohm) | ISD04N65A, QM3004D, LS64 10L45 SBR |
| Standby PWM Controller | On - Bright OB5282 | On-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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