Corsair RM750x (2024) PSU review

Corsair, established in 1994, initially made its mark by producing high-performance memory modules for PCs. Over the years, the company has expanded into various sectors of the gaming and PC hardware markets, including power supply units (PSUs) market Today Corsair is offering dozens of PSUs through several series, catering to seemingly every PC enthusiasts’ needs.

In this review, we will focus on Corsair’s latest addition to its RMx series, the RM750x (2024) PSU. With a power output of 750 watts and compliance with the ATX 3.1 standard, this unit offers a compelling set of features, including individually sleeved cables and a 12+4 pin connector for compatibility with the latest high-performance graphics cards. It meets Cybenetics Gold efficiency certification, designed to combine performance and reliability with longevity and aesthetics for users seeking a high-quality PSU in a mid-range power capacity.

Specifications and Design

In the Box

The Corsair RM750x (2024) PSU comes in sturdy cardboard packaging with the signature black and yellow Corsair colors. Inside, the PSU is protected by a nylon pouch and cardboard inserts to ensure safe transit.

The bundle includes mounting screws, an AC power cable, several cable ties, and cable combs. Corsair has moved towards more environmentally friendly packaging by replacing plastic bags with paper.

The unit features all-black cables, which are individually sleeved for added flexibility and im proved aesthetics. There is a single 12+4 pin cable and three 6+2 pin PCI Express cables, with an equal number of device connectors. However, the 12+4 cable uses two of the 6+2 pin connectors at the PSU's side, limiting the number of cables that can be connected simultaneously, which is intentional given the power output of the unit.

External Appearance

The Corsair RM750x (2024) PSU features a satin black chassis. At 160 mm in length, the PSU is slightly larger than the standard ATX specification, but the extra length was a necessary evil to accommodate the 140 mm cooling fan. Despite the larger size, it should maintain compatibility with the majority of mid- and full-tower cases.

The PSU’s aesthetic design reflects Corsair’s attention to detail, with chamfered edges giving the unit a refined, modern look. The black finish is smooth and understated, lending the PSU a premium feel. Both sides of the unit are adorned with decorative stickers. The fan grille at the top is part of the chassis itself, integrating a unique geometric pattern that is meant to complement the overall design.

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On the rear of the unit, the standard on/off switch and AC power receptacle are positioned alongside a rheostat switch, which allows users to control the PSU’s hybrid fan mode. This switch offers flexibility, enabling the fan to run continuously or operate in a thermally-controlled mode that keeps fan noise minimal at low loads – however,a rheostat also allows the user to decide what the minimum speed of the fan will be if the hybrid mode is disabled. This feature allows for advanced users to disable the hybrid mode and set a minimum speed that does not bother them with noise, improving the unit’s electrical performance and longevity. The connectors at the front of the unit are recessed into the body, with a subtle legend surrounding them.

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Internal Design

The Corsair RM750x PSU utilizes a 140 mm Corsair NR140HP fan with a fluid dynamic bearing (FDB) engine, designed to balance acoustics and reliability. The maximum speed of the fan is measured at approximately 2200 RPM.

The RM750x (2024) is built on a platform developed by Channel-Well Technology (CWT), a recognized OEM known for its reliable PSU designs and frequently used by Corsair for their mid- and top-tier units. The filtering stage consists of six Y capacitors, two X capacitors, and two filtering inductors, followed by a single rectifying bridge mounted on a heatsink positioned immediately after the filtering stage.

The Active Power Factor Correction (APFC) circuit features two 60R190P6 MOSFETs and one diode mounted on a heatsink, with a FET supporting low-load efficiency. The passive components are two Nippon Chemi-Con 105°C capacitors—one rated at 470 μF and another at 390 μF—and one fairly large encased coil. The primary stage employs two Infineon 60R190P6 MOSFETs in a half-bridge configuration, located on a separate heatsink adjacent to the main transformer.

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On the secondary side, four Toshiba TPHR85 MOSFETs generate the primary 12V line, while DC-to-DC circuits on a vertical daughterboard at the edge of the main PCB produce the 3.3V and 5V lines. The secondary capacitors are sourced from reputable Japanese manufacturers such as Nippon Chemi-Con and Nichicon, with a few Rubycon electrolytic capacitors in the midst.

Cold Test Results

Cold Test Results (25°C Ambient)

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts.

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During cold testing, the Corsair RM750x (2024) comfortably meets its certification requirements and more – if the Cybenetics testing was done at room temperature, it would achieve Platinum status. At 115 VAC, the PSU achieves an average nominal load efficiency of 89.6%, which improves to 91.9% when using a 230 VAC input. The efficiency peaks around 50% load, typical for most PSUs, and the unit maintains good performance across the nominal load range (10-100%). There is a severe 2.3% efficiency drop when using a 115 VAC input, yet the RM750x keeps meeting its certification requirements. Its performance at very low loads is also commendable.

The fan in the Corsair RM750x starts operating when the PSU reaches approximately 300 watts of load. It remains relatively quiet at lower loads but gradually increases in speed as the load rises. Even under full load, the fan does not reach its maximum speed when operating at room temperature; however, it will be audible in a busy environment. Internal temperatures stay well within safe limits under these operating conditions.

Hot Test Results

Hot Test Results (~45°C Ambient)

During hot testing, the Corsair RM750x (2024) experiences a significant decrease in efficiency, mostly under heavy loads. Efficiency drops to 88.1% at 115 VAC and 90.4% at 230 VAC, compared to 89.6% and 91.9% during cold testing. This efficiency degradation of approximately 1.3% is atypical for a high-quality unit but there are no signs of thermal stress. Unfortunately for the RM750x, this degradation causes it to lose the Platinum certification.

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In these warmer conditions, the fan of the Corsair RM750x activates much sooner than during cold testing, starting almost immediately when the load surpasses 100 watts. The fan speed increases progressively with the load, reaching near its maximum speed under sustained heavy loads. Although the fan does become loud when the unit is heavily loaded, it is very well balanced between thermal performance and acoustics for a PSU of this class.

PSU Quality and Bottom Line

Power Supply Quality

The Corsair RM750x (2024) exhibits spectacular electrical performance considering its price range and class. Voltage regulation is excellent, with the 5V rail showing a deviation of 0.5%, the 3.3V rail at 0.4%, and the 12V rail at 0.7%, ensuring stable output under various load conditions. Ripple suppression is even more impressive, with maximum ripple values of 34 mV on the 12V line, 16 mV on the 5V line, and 16 mV on the 3.3V line. These figures are almost a quarter of what the design guide dictates to be the limit.

During our assessment, we evaluate the essential protection features of every power supply unit we review, including Over Current Protection (OCP), Over Voltage Protection (OVP), Over Power Protection (OPP), and Short Circuit Protection (SCP). All protection mechanisms were activated and functioned correctly during testing.

The OCP is calibrated to activate at 136% for the 3.3V rail, 134% for the 5V rail, and 120% for the 12V rail, allowing the PSU to handle temporary overloads effectively without compromising performance or safety. The Over Power Protection (OPP) is set at 120%. These settings are sharp, significantly sharper than what we were used to with ATX 3.0 units, but will not be a problem unless the RM750x is significantly undersized for the system it is powering.

Bottom Line

The Corsair RM750x (2024) offers a solid mix of performance, efficiency, and features, making it a reliable choice for mid-to-high-end PC builds. Designed with compliance to the ATX 3.1 standard, it brings modern connectivity and performance enhancements that will benefit users looking for a future-proof power supply. The inclusion of the 600W PCI Express connector may be a little bit overkill for its wattage, but it also makes the RM750x a versatile choice for gaming PCs – it has enough power to handle a top-tier graphics card if paired with a mainstream gaming processor and few other components. We also appreciated its full modularity and sleek black cables, which makes it well-suited for clean gaming builds, particularly for those integrating new or upcoming GPUs. The use of all-Japanese capacitors is the first hint that the designer aimed to ensure durability, and Corsair’s choice of components overall suggests a unit built for reliability and long-term performance. The 140mm fan operates quietly at lower loads (or not at all) and only ramps up noticeably during higher load scenarios.

In terms of performance, the RM750x delivers excellent voltage regulation across all rails, with deviations well within safe margins even under demanding loads. The ripple suppression, particularly on the critical 12V rail, is impressive for a unit in this price range, offering a clean and stable power output that ensures the longevity of connected components. As for its efficiency, it is very high while the RM750x operates at room temperature but degrades significantly as the temperature increases – a behavior that cost the unit a Cybenetics Platinum efficiency rating. Still, it easily managed to get a Gold certification.

However, while the RM750x shines in many areas, there are some drawbacks to consider. At a retail price of $120, it sits in a competitive segment where other units offer similar or slightly better features for a lower cost. Its Gold certification is adequate but can be considered lacking compared to what is available at this price point. Additionally, while the overall design and performance are solid, it does not break new ground compared to earlier models, offering more of an incremental update rather than a major leap forward. In conclusion, the Corsair RM750x (2024) is a dependable power supply with modern features and strong performance. For those needing an ATX 3.1-compliant PSU with a focus on stability and quiet operation, it is a solid option, though budget-conscious users may be looking elsewhere or otherwise waiting for a sale.

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