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Corsair RM650 Power Supply Review: Silent and Efficient

Our Verdict

The Corsair RM650 is a very good choice in the mid-wattage market, but its slightly-superior sibling costs only a little bit more.

For

  • Full power at 47 degrees Celsius
  • High performance
  • Quiet operation
  • Fully modular
  • Supports Modern Standby mode
  • Efficient under light loads
  • Ten-year warranty

Against

  • Only a few bucks/pounds less expensive than the RM650x
  • No option to deactivate semi-passive operation
  • The top-notch NR135L fan has been replaced by a Hong Hua one

Specifications and Part Analysis

Corsair RM650 Power Supply. ( (Image credit: Tom's Hardware))

The Corsair RM650 has high performance in almost all areas and it is dead silent. Its only major downside seems to be the small price difference with the RM650x, which has better capacitors and a higher quality fan. Nonetheless, the RM650 scores higher efficiency under super-light loads and it also supports Windows 10's Modern Standby mode. If the price difference with the RM650x is close to 20 dollars (16 pounds) then the RM650 is a good deal, but with only 10 dollars (8  pounds) difference it will be a tough sale.

We have reviewed both the Corsair RM850 and RM750 so far, and we found them to be excellent. The time has come to take a detailed look at the smallest member of the line, the RM650, which as the model number implies, has 650W max power. The Corsair RM650 is a fully modular power supply, able to support a potent system thanks to the two EPS and four PCIe connectors that is equipped with.

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The significant differences with the slightly more expensive RM650x come down to the cooling fan and the capacitors. The RM650 uses a 140mm Hong Hua fan and Chinese Elite caps, while the RM650x is only equipped with Japanese caps and the high-quality NR135L fan. Nonetheless, there are some areas where the RM650 takes the lead because it uses an updated platform. Its efficiency under super-light loads is high, and it also supports Windows 10's new Modern Standby mode, which allows the PC to boot reliably within a five seconds period.

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Specifications

Manufacturer (OEM)CWT
Max. DC Output650W
Efficiency80 PLUS Gold, ETA-A (88-91%)
NoiseLAMBDA-A+ (15-20 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
Weight1.55 kg (3.42 lb)
Form FactorATX12V v2.4, EPS 2.92
Warranty10 Years

Power Specifications

Rail3.3V5V12V5VSB-12V
Max. PowerAmps20205430.3
Watts130648153.6
Total Max. Power (W)650

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) 2416-18AWGNo
SATA (500mm+100mm+100mm)2618AWGNo
4-pin Molex (450mm+100mm+100mm+100mm)1418AWGNo
AC Power Cord (1420mm) - C13 coupler1116AWG-

It is nice to see a pair of EPS connectors in a 650W power supply. The number of PCIe is adequate for this wattage category, and the same goes for the SATA and 4-Pin Molex connectors. The problem with the peripheral connectors is the short distance between them. Ideally, it should be 150mm.

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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 understand better the components we're about to discuss.

General Data
Corsair RM650 (2019)Corsair RM650x
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
Bridge Rectifier(s)2x GBU806 (600V, 8A @ 100°C)1x GBU1506 (600V, 15A @ 100°C)
APFC MOSFETS2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ohm)1x Infineon IPW60R125P6 (650V, 19A @ 100°C, 0.125 Ohm)
APFC Boost Diode1x Power Integrations QH08TZ600 (600V, 8A @ 95°C)1x Vishay 8S2TH061 (600V, 8A @ 120°C)
Hold-up Cap(s)2x Su'scon (400V, 330uF & 270uF each or 600uF combined, 2,000h @ 105°C, LZ)1x Nippon Chemi-Con (400V, 680uF, 2000h @ 105°C, KMR)
Main Switchers2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ohm)2x Toshiba TK18A60V(600V, 18A, 0.19 Ohm)
APFC ControllerChampion CM6500UNX & CM03X Green PFC ControllerInfineon ICE3PCS01G - CM03X
Resonant ControllersChampion CU6901VInfineon ICE2HS01G
TopologyPrimary side: Half-Bridge & LLC converter Secondary side: Synchronous Rectification & DC-DC convertersPrimary side: Half-Bridge & LLC Resonant Converter Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETS4x International Rectifier IRFH7004PBF (40V, 100A @ 25°C, 1.4mOhm)4x Sinopower SM4021NAKP (40V, 100A @ 100°C, 2.7 mOhm @ VGS=6V)
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 uP3861PDC-DC Converters: 2x QM3006D & 4x QM3004D FETsPWM Controller: 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, NICElectrolytics: Chemi-Con (105°C, KZE & KZH series) Polymers: Nippon Chemi-Con
Supervisor ICWeltrend WT7502 (OVP, UVP, SCP, PG) & LM393GWeltrend WT7502
Fan ControllerMicrochip PIC16F1503-
Fan ModelHong Hua HA1425M12F-Z (140mm, 12V, 0.36A, Rifle Bearing Fan)NR135L (12 V, 0.22 A, Rifle Bearing)
5VSB Circuit
Rectifier1x Unisonic Technologies 4N65L (650V, 4A @ 25°C, 2.5Ohm)PFR20V45CT (45V, 20A, VF: 0.42V max @ 125°C)
Standby PWM ControllerOn - Bright OB5282On-Bright OB5269
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The RM650 uses an upgraded platform, provided by the same manufacturer (CWT) that made the RM650x. There several essential differences between those two platforms, as you can see in the table above. The areas where the RM650x wins are the higher quality Japanese caps and the NR135L fan. On the other hand, the RM650 uses a new resonant controller, allowing for higher efficiency under light loads, and it is equipped with an electromagnetic relay which enhances its inrush current protection. On top of that, it uses a micro-controller in the fan control circuit so Corsair can easily tune the fan's speed and provide the ideal fan speed profile.

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We should note here that Elite caps, which are widely used in the RM650, might be manufactured in China, but Elite is a brand of Chinsan. The latter is a Taiwanese company, with factories in China, and provides products to several high-end brands including two well-known ones. This means that Elite caps are of good quality and you shouldn't be afraid, in any case, of their Chinese origin. Sure there are enough Chinese factories with low production standards, and when it comes to capacitors, this can lead to terrible results. Nevertheless, Elite products have been proven reliable so far, and this is why most brands prefer them when it is too expensive to use Japanese caps.

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The soldering quality is good, as expected from CWT.

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  • Dark Lord of Tech
    Thanks Aris , greatr review as usual.
    Reply
  • jonnyguru
    Some background:

    The new Intel specification requires better efficiency at 2%-10% load and new timings (T1 and T3 to support modern standby mode). This was not easy/cheap to achieve, so Corsair couldn't just replace the current RMx in the market with a new, more expensive version without tangible differences. So the capacitors and fan was "down graded" (though Hong Hua is a fantastic fan manufacturer) to allow this "new version" of the RM to meet an acceptable price point.

    Fun fact: Removing the caps from the cables saved A LOT of money. As you can see, it didn't have much impact. The caps in the cables in other models are only there to appease reviewers (like Aris) that compare ripple from one model to the next within mV of each other.
    Reply
  • Aris_Mp
    jonnyguru said:
    Some background:

    The new Intel specification requires better efficiency at 2%-10% load and new timings (T1 and T3 to support modern standby mode). This was not easy/cheap to achieve, so Corsair couldn't just replace the current RMx in the market with a new, more expensive version without tangible differences. So the capacitors and fan was "down graded" (though Hong Hua is a fantastic fan manufacturer) to allow this "new version" of the RM to meet an acceptable price point.

    Fun fact: Removing the caps from the cables saved A LOT of money. As you can see, it didn't have much impact. The caps in the cables in other models are only there to appease reviewers (like Aris) that compare ripple from one model to the next within mV of each other.

    Thank you Jon for the explanation on why the price had to drop so little compared to the RMx. Every time there is an ATX change, the production cost goes higher :(

    the in-cable caps provide the wow factor he he.
    Reply
  • refillable
    Aris_Mp said:
    Thank you Jon for the explanation on why the price had to drop so little compared to the RMx.

    Wait, saw this review earlier but I realized that it has Su'scon caps. Su'scon is the "avoid" tier in your own capacitor tier list. Red flag? Makes me think that this series is even more useless than I previously thought especially that the RM650X can be bought for so cheap these days.
    Reply
  • jonnyguru
    refillable said:
    Wait, saw this review earlier but I realized that it has Su'scon caps. Su'scon is the "avoid" tier in your own capacitor tier list. Red flag? Makes me think that this series is even more useless than I previously thought especially that the RM650X can be bought for so cheap these days.

    Aris has yet to visit a capacitor factory.
    Reply
  • refillable
    jonnyguru said:
    Aris has yet to visit a capacitor factory.
    I don't get it, but I pretended I do :LOL:
    Reply
  • jonnyguru
    refillable said:
    I don't get it, but I pretended I do :LOL:

    Since moving from being a reviewer to someone working in the industry, I've learned that 75% of what is said in reviews, including a lot of the stuff I have said in reviews, is total B.S.
    Reply
  • refillable
    jonnyguru said:
    Since moving from being a reviewer to someone working in the industry, I've learned that 75% of what is said in reviews, including a lot of the stuff I have said in reviews, is total B.S.

    Thanks for clearing that up.
    Reply