Corsair RMi Series RM650i Fully-Modular Review

Introduction & Packaging Corsair is one of the biggest names in the industry, covering a wide range of products from chassis, peripherals, cooling, audio and more importantly today, power supplies. Their latest range of PSUs promises to deliver some impressive performance figures and we've got two of their new RMi series products on our test bench and ready to rock. First up, we have the 650 watt unit, which to some may not sound like a lot of power, but from my experience, few systems pull more than 500 watts even at full load, so there's no doubt in my mind that this unit is the one aimed at mid to high-end gaming systems and day-to-day users. The RMi series is a big improvement on the current RM series of PSUs. They still offer the high-end features of the previous generation, such as 80 Plus Gold Certification, modular cables and more. With the added bonus of a 7-year warranty, full Japanese capacitors, a fluid dynamic bearing fans, digital output (Corsair Link), custom fan profiles and something for the enthusiast crowd, the ability to switch the +12v rail between multiple and single rail modes. "Corsair RMi Series power supplies are fully modular and optimized for silence and power efficiency. Zero RPM Fan Mode means that the fan doesn’t spin until the power supply is under heavy load, and the fan itself is custom-designed for low noise operation even at high loads. 80 PLUS Gold rated efficiency saves you money on your power bill, and the flat black cables are fully modular so you can enjoy fast, neat builds. The Corsair RMi Series is built with high-quality components, including all Japanese electrolytic capacitors, and is guaranteed to deliver clean, stable, continuous power, even at ambient temperatures as high as 50°C. Users can also install Corsairs Link software to monitor power usage and fan speed. With 650W, 750W, 850W and 1000W models available there is a Corsair RMi power supply suitable for potentially any PC configuration." - Corsair Packaging and Contents The packaging is nicely designed, with a clear image of the PSU on the front of the box, as well as detailing the 7-year warranty and 80 Plus Gold certification. In the box, you'll find a power cable, some cable ties and mounting screws, the warranty guide and user manual. There was also a USB drive included, but at this time we think this may only be for press, not for consumers, as it contained information about the testing in-house of the power supply. A Closer Look - Exterior Power Supply Unit First impressions of the RM650i are very good, the design is certainly appealing, at least as appealing as you could expect from a PSU. The top section has a nice fan guard and the housing of the PSU has a similar pattern that matches up, giving it a nice uniform look. The black finish on the PSU is nothing special, but it's got a light texture to it that looks presentable enough. The sticker on the side is nice and simple too, so it should blend in with most system builds easily enough. Here you can see the RM650i supports a good load level on each rail, with up to 54A on the +12v rail as well as an overall total of 650W, although we'll find out the true numbers shortly in our testing. There's all kinds of fun stuff going on here! First and most importantly is the Corsair link, which can be accessed via a 12C connector or the mini-USB port. There's a LED indicator and one feature I really like, a fan test button. The fan test is great since this PSU can run passively, you may feel the need to check the fan still actually works, this should help alleviate your concerns. The PSU features a full modular design. There are four six-pin connectors for peripherals and SATA/Molex connectors, three eight-pin connectors, which can be used for the 4+4 CPU connector, as well as 6+2 PCI-E power cables. One of the things you may have noticed is that the 24-pin actually has 28-pins. There are extra "sense wires" on many of the connectors which the PSU uses these to help monitor and regulate the voltage. There's a good amount of ventilation around the back. Cabling All of the included cables are of a high quality and good length. What does please me is that the included cables are all black, with black braiding and black connectors and this will help give your system build a more uniform look overall. The SATA and MOLEX connectors are all flat cables which are much easier to work with in terms of cable managements. A Closer Look - Interior It's immediately clear that a lot of care has gone into the design and construction of this PSU, it's surprisingly neat and tidy in there. Manufactured by CWT, we can see that in the top left you can see four (secondary) output capacitors. The main bulk capacitor is rated up to 400v, 680uF and 105C. Here you can see the AC socket, EMC/EMI filtering. The modular connector board which includes extra caps for voltage stabilisation and regulation, which are further assisted by the extra sense wires on the modular cables; you'll see this in action shortly. The LLC main transformer, which has the Corsair sticker over the top. The smaller PCB is the MCU for Link compatibility and for connecting the power supply fan. The 135mm fan comes with a fluid dynamic bearing, which promises to be even quieter than the fans used in Corsair's previous RM series PSUs. Test Procedure At eTeknix we take the power supply testing procedure very seriously and have invested a lot of resources into acquiring the appropriate testing equipment. For all power supply reviews we test the power supplies with dedicated power supply testing equipment. This means we are able to get the most accurate results from our testing as opposed to using software benchmarks (such as OCCT) or multi-meter readouts which are broadly inaccurate. Our test machinery is as follows: Sunmoon SM-5500ATE Active Load Tester (1200W rated) Stingray DS1M12 USB Oscilloscope Voltcraft DT-10L laser tachometer The eTeknix test procedure involves: Testing each power supply at 20/40/60/80/100% load (with balanced load across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power "pulled at the wall") and voltage regulation (deviance from expected voltages of 3.3/5/12 on the main rails). Measuring ripple with an oscilloscope at 20/40/60/80/100% load. Measuring fan speed after a stabilisation period of five minutes at each load scenario using the Voltcraft DT-10L laser tachometer and a reflective strip on the fan. Testing each power supply's OPP (Over Power Protection) mechanism and seeing how many watts each power supply can deliver before shutting down Other things to consider are that We recognise that a single yellow 12 volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) and so we used an adequate number of cables for each power supply to ensure there is not efficiency loss from poor cables selection Our Sunmoon SM-5500ATE power supply tester is not capable of testing more than 300W on each of the 12 volt rails so where a power supply provides more than 300W on a 12 volt rail that power is distributed over multiple 12 volt rails on the load tester. For example a power supply with one 12 volt rail supplying 750 watts would be spread equally over three 12 volt rails on the load tester, a power supply with two 450W 12v rails would be spread over four 12v rails on the load tester, two 225W 12v rails for each of the 12v rails on the unit. We use the same time scale and horizontal millivolt scale on our oscilloscope for all ripple tests, that is a 20ms T/DIV (horizontal) and a 0.02 V/DIV (vertical) meaning the scale is from -80mV to +80mV, ATX spec dictates that the 12v rail must fall within 150mv of ripple and the 3.3/5 within 50mv so that scale allows us to include both 150 and 50mV peaks. (Some older PSU reviews use different scales which were later ditched as the visual representation they give is inadequate, in these reviews written measurements are provided only). Deviance is the terminology used to represent the way voltages diverge from the expected values Efficiency, PFC and Voltage Regulation Voltage Regulation To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage. The voltage regulation on this unit is very impressive, well within the safe margins overall. -12v regulation could be a little stronger, but at least the output is fairly consistent across the load range. Power Efficiency Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies. The PSU exceeds our expectations here, with the efficiency never dropping below 90% overall, with the PSU peaking in efficiency at 40%, around the point the built-in fan would kick in. Power Factor Correction Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source - Wikipedia). PFC was very good overall, especially in load scenarios above 40% (non-passive mode). Ripple Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs. millivolt ripple is measured by the peak to peak size of the voltage curve. The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications. Millivolt figures are stated to the closest increment of 5 given their variability. Load (%) 3.3V Ripple 5V Ripple 12V Ripple 20 3 3.4 4.2 40 3.4 4.2 5.4 60 3.8 4 6.4 80 44.4 5.4 9.4 100 4.6 6.4 12 This was quite a surprise for us, so much so that we had to re-test just to be certain that the results were correct. The ripple suppression is exceptional, to say the least, easily the best we've ever seen! This is due to the caps on the added PCB board which filter at the modular connectors. 3.3 volt @ 100% 5 volt @ 100% 12 volt @ 100% Over Power Protection and Max Wattage Power supplies often quote as having various protection mechanisms such and the most important of these is Over Power Protection. In our testing we crank up the power draw until the power supply either shuts down (meaning the OPP mechanism is present and working) or blows up (meaning it is either not present or not working). We then note the maximum power consumption before the power supply shut down (or blew up). This may be a 650W unit, but we managed to get it just shy of 800W before the OPP kicked in! While not ideal to run it this hard all the time, it's good to know that if you do get a spike in your power requirements, your system shouldn't skip a beat. Fan Speed When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Sunmoon test equipment and air conditioning corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. The ambient temperature during testing held constant at 22 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario. In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used. Below 800 RPM - Inaudible/Silent 800 to 1000 RPM - Barely audible 1000 - 1200 RPM - Audible but still quiet 1200 - 1400 RPM - Moderately noisy 1400 - 1800 RPM - Noisy 1800 RPM or higher - Intolerable Incredible performance here, as the unit runs completely passively up to 40% load, yet even at maximum RPM, you can expect it to be barely audible, great for those who are trying to build a silent system. Final Thoughts Pricing The Corsair RMi Series 650W fully modular power supply can be purchased from Overclockers UK for a very reasonable £104.99. This is a little expensive for a PSU of this power output, but when you factor in the build quality, Corsair link features and semi-passive operation, it's very impressive indeed. Conclusion Corsair has gone all out on this unit, bringing many enthusiast grade features to a consumer friendly product, without the enthusiast price tag. Sure you're going to pay a premium, but as you've seen in our testing, it will be money well spent. The RMi 650W ticks a lot of boxes just on performance figures alone, offering impressive efficiency and ripple suppression, a semi-passive fan design for silent operation under day-to-day usage scenarios and more. The addition of the ever popular Corsair Link is always welcome, allowing you to monitor and log fan speed, voltage, power consumption and more from your desktop, as this will help you get a better command over your system and could prove very handy when overclocking your system. Build quality is exceptional, with the use of all Japanese 105c capacitors, high-quality modular cables, a Fluid Dynamic Bearing 135mm fan, fan test control and more. The RMi is certainly going to look great in your system for years to come and the confidence added by a seven-year warranty is a sure sign that Corsair know this is a great product. Pros Fully modular cables Incredible seven-year warranty Exceptional ripple suppression Semi-passive design Fan-test button Corsair Link Switchable single/multiple 12v rail Sense wires + extra capacitors for voltage and ripple regulation Cons None Neutral More expensive than other 650w units, but you get a lot in return for the extra investment "The RMi 650W is one of the best PSUs we've tested, especially so within this wattage range. The semi-passive operation and the seven-year warranty alone make it worth paying the premium for Corsairs latest power supply." Thank you Corsair for providing this review sample.