Corsair RM650 Power Supply review

1. Introduction2. Corsair RM650 (Bundle & Cables)3. Corsair RM650 (External)4. Corsair RM650 (Internal)5. Corsair RM650 (Super High Res Gallery)6. Testing Methodology & Results7. Closing Thoughts8. View All Pages

Corsair have earned a respected place in the minds of the enthusiast user over the years having produced a wide range of quality memory, cases, headsets, solid state drives, keyboards and power supplies.

Today we look at one of their new power supplies in the ‘RM' range – the RM650. The company are also releasing a RM450, RM550, RM750, RM850 and RM1050 model to suit all systems. All of the RM range is 80 Plus Gold Certified, pure modular and is designed with low noise as a primary focus.

All of the new RM power supplies are Corsair Link ready – meaning you can monitor the power supply fan speed and +12V output from the desktop software. This will be a welcome addition for those people who already have a Corsair Link system set up on the system.

Corsair claim to have placed a focus on the noise characteristics of this range. Corsair say “We are  aware of our customers desire to have the quietest components, so we utilize a neutral third party sound lab to test the noise level of our designs using an industry standard testing methodology (ISO 7779:2010). The result is the NR135L PSU fan.”

The RM series of power supplies operate in zero RPM fan mode for up to 40% of the power supplies maximum load (at 25c room temperature). The idea is to ensure that the power supply is silent for most duties, such as surfing the net, checking email or social gaming. When the load gets higher the thermally controlled fan will gradually spin up, such as when gaming.

Product features:

• Optimized for Silence: The components used to manufacture the RM Series are manufactured specifically for excellent performance and low audible noise.
• 80 PLUS Gold-certified Efficiency: Highly efficient RM Series power supplies produce less heat and have lower operating costs.
• Flat black, Low-Profile Modular Cables: You can use only the cables you need, and leave the rest in the box for fast, easy, and great-looking builds.
• Reliable, Continuous Power Delivery: Corsair uses high-quality internal components, and RM Series power supplies are guaranteed to deliver clean, stable, continuous power.
• Corsair Link Compatible: RM Series power supplies connect to Corsair Link software for real-time monitoring of fan speed and power delivery directly from your desktop. Additional hardware required for 450W-850W units.
• The latest ATX12V v2.4 and EPS 2.92 standards and it is backward compatible with ATX12V 2.2, 2.31 and ATX12V 2.01 systems.
• 4th generation Intel® Core™ processor Ready (Intel Haswell and Z78 motherboards)
• 80PLUS Gold certified, delivering over 92% energy efficiency at real world load conditions.
• The completely modular cable system allows you to use only the cables you need.
• Low-profile, flat cable design reduces air friction and helps maximize airflow through your computer’s chassis.
• High-quality capacitors provide uncompromised performance and reliability.
• A five year warranty and lifetime access to Corsair’s legendary technical support and customer service.
• Active Power Factor Correction (PFC) with PF value of 0.99.
• 135MM NR135L Noise reducing fan. MTBF: 100,000 Hours
• Universal AC input from 100~240V.
• Multi-GPU Ready
• Over-voltage and over-current protection, under-voltage protection, and short circuit protection, over power protection, over temperature protection provide maximum safety to your critical system components.
• Safety and Agency Approvals: FCC, ICES, CE, C TUV US, RCM, TUV, CB, CCC, BSMI, GOST, ROHS, WEEE, ROHS, KC

Corsair Box artwork is always attractive, and the RM650 ships in a lovely looking package featuring a high resolution picture of the power supply fan.

No fancy felt bag inside this box. The power supply itself ships sandwiched between two cardboard ‘egg' boxes, wrapped in a clear bag.

On top is some literature on the Corsair range of products, cable ties, mounting screws, modular cables and a regional specific power cable.

Above is a table showing the various cable configurations of the new Corsair RM range. The RM650 we are reviewing today has four 6+2 PCIE connectors – the same as the 750W model. All of the cables are the thin ribbon style which are easy to route and hide behind panels. There are eight SATA cables and seven Molex cables.


The Corsair RM650 is an attractive power supply, finished in plain black with white and yellow product branding on the sides.

The large 135mm fan can be seen behind the grill – we will take a closer look at this later in the review.

The unit passed our ‘screwdriver’ stress test, which involves running a Philip’s head driver down the side of the chassis with weak to modest pressure. How often have you accidentally hit a power supply with some tools during a system build phase?

One side of the power supply is vented to help with air flow. At the side is a power switch and connector. The company attach a little sticker to explain the ‘silent operation' at ‘low to moderate loads'.

The modular panel resides on the other side of the chassis and is clearly labelled to help ensure the installation phase is as painless as possible. There is also a CLINK connector here if you want to use the Corsair software.

Corsair RM650 Power Supply
DC Output	+3.3V	+5V	+12V	-12V	+5Vsb
Max Output	25A	25A	54A	0.8A	3A
Total Power	130W		650W	9.6W	15W
	650W

The single 12V rail can deliver 54A. Both +3.3V and +5V output can deliver 25A.


Corsair are using a new 135mm fan – model number NR135L. The company have said that the custom designed fan has an optimised blade profile for low turbulence airflow and near silent operation, even at full speed. The fan is rated for 0.22A at 12VDC.

The overall build quality is quite high and there is plenty of space around the PCB for air to circulate. They look to be using CWT as their partner for this particular design.



This power supply uses DC to DC converters to create the 3.3V and 5V output from the +12V rail. The daughter card can be seen in some of the images.

Corsair are using high grade 105C Japanese capacitors throughout. The primary capacitor is rated 470uF, 400V @ 105c. The secondary side uses Japanese electrolytic capacitors for filtering, alongside some solid polymer capacitors mounted on the DC to DC converter board.

On this page we present some super high resolution images of the product taken with the 24.5MP Nikon D3X camera and 24-70mm ED lens. These will take much longer to open due to the dimensions, especially on slower connections. If you use these pictures on another site or publication, please credit Kitguru.net as the owner/source.

Additional technical assistance: Peter McFarland and Jeremy Price.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
152W	2.05	3.30	2.04	5.03	10.12	12.15	0.50	5.01	0.20	-12.07
270W	3.03	3.29	3.05	5.03	19.14	12.08	0.50	5.00	0.30	-12.05
400W	4.05	3.28	5.02	5.01	29.18	12.02	1.00	5.00	0.30	-12.06
523W	6.09	3.26	7.04	5.00	38.18	11.94	1.50	5.01	0.30	-12.07
650W	8.00	3.25	9.00	4.98	48.00	11.89	2.50	5.00	0.30	-12.07

Load regulation is quite good, although we have seen better in recent months from some competing products.

Corsair RM650 Power Supply	Maximum Load
	708W

The power supply would shut down at 708W, gracefully. The protection circuitry worked well.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
590W	1.0	3.30	1.0	5.03	48.0	11.88	0.2	-12.02	0.50	5.03
145W	12.0	3.22	15.0	4.94	2.0	12.14	0.2	-12.01	0.50	5.03

Cross load results are decent, if not remarkable. There is noticeable droop on the +12V output when hit with 48A, although it is nothing to be concerned about.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum. ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
152W	15	15	25	25
270W	20	20	25	25
400W	20	20	30	25
523W	20	20	35	30
650W	25	20	50	35

Ripple suppression falls within the rated tolerance guidelines. The +3.3V and +5V output peak at 25mV and 20mV respectively. The +12V output hits 50mV at full load which is well within the rated guidelines.

Efficiency (%)
152W	90.51
270W	92.21
400W	91.73
523W	89.33
650W	89.44

Efficiency is very impressive – peaking just over 92 percent at 50 percent load. At full load this drops to around 89.5 percent efficiency.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the Power Supply we have taken it into our acoustics room environment and have set our SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
152W	<28.0
270W	<28.0
400W	29.2
523W	31.4
650W	33.9

The fan profile is superb, and this power supply is basically inaudible until over 500W is demanded and the fan starts to spin up. The good news is that thanks to the high efficiency, even at full load it is very quiet.

Temperature (c)
	Intake	Exhaust
152W	36	39
270W	39	44
400W	42	48
523W	43	54
650W	45	57

The large fan spins slowly through the load range, spinning up between 500 watts and 650 watts.

Maximum load	Efficiency
708W	88.4

Pushing the PSU above its rated limits generates an ultimate efficiency level of around 88.4%. This is not a viable ‘real world’ situation, but its interesting nonetheless.
The market today seems literally flooded with power supplies from a variety of manufacturers. Corsair however have a very special place in the hearts and minds of the enthusiast user, especially when it comes to their power supply range.

Corsair's new RM650 supply is set to target the demanding enthusiast user who requires 80 Plus Gold Certification, a pure modular design and ultra low noise levels. On paper it certainly ticks all the right boxes.

First impressions are positive. The quality of the paintwork is high and proves resilient to both fingerprints and careless handling during a system build. The flat, ribbon style modular cables will appease system builders who need to route and hide unsightly wiring out of sight. The cables are all very long as well, ideal for builds within tall full tower designs.

Technically the unit is solid, if unremarkable. Load regulation could have been better, although there are no causes for concern based on our results. Equally so, ripple suppression fell within rated industry tolerance guidelines, although we have seen better results from some high grade competitor products in the last year.

Efficiency is excellent, achieving 80 Plus Gold Certification with flying colours. This high level of efficiency ensures that the large 135mm custom fan never has to work that hard, even under high load.

Most of the time this power supply will be silent and unless you are pushing it to within the last 10% of power draw, it will be basically inaudible. Below 400W and the fan either won't be spinning or it will be rotating so slowly it would be almost impossible to hear under normal circumstances. If you need load above 550W on a regular basis, then we would recommend you aim higher up the food chain anyway, perhaps at a 750W model.

Right now you can buy the Corsair RM650 from Overclockers UK on a special deal for £89.99 inc vat. At this price and considering the all round package it really does deserve a recommendation.

Pros:

• very quiet.
• high quality paintwork.
• pure modular design.
• flat cables.
• 105c capacitors.

Cons:

• A lot of competition at the price.

Kitguru says: A solid all round unit which delivers high quality power without making a racket.

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