Introduction & Packaging
The world of Small Form Factor (SFX) power supplies has been a fierce battleground over the last few years. Gaming systems have been getting smaller, the HTPC and Steambox markets are growing in popularity and the demand for a tiny PSU that can keep the system small, but still deliver the high-performance grunt required by modern gaming GPU/CPU combos is at an all time high. Enter the new Corsair SF600, the latest contender on the market and judging by the specifications, it may be the best one we’ve seen to date.
“SF Series power supplies bring legendary Corsair performance and reliability to the SFX small form factor standard. They have the features found in full-size high performance power supplies, with certification for 80 PLUS Gold efficiency, superior voltage regulation, Zero RPM mode for virtually silent operation, and 105°C All Japanese capacitors for better reliability.” – Corsair
Equipped with 600W of power, more than enough for any high-end and overclocking gaming rig with a single GPU, 100% Japanese 105c capacitors, a zero RPM fan mode for ultra quiet performance at lower loads, fully modular cables and that super compact SFX form factor, the SF600 is certainly an attractive unit. To make the deal even sweeter, it comes backed up by Corsairs confidence inducing 7-year manufacturers warranty!
The packaging is very nicely designed, keeping in theme with other current Corsair product ranges and featuring a clear product image and the main specifications prominently displayed.
Plenty of technical information around the back too, showing off the efficiency and fan speeds at various load scenarios.
In the box, you’ll find two protective bags, one for the cables and another containing the PSU. There is all the usual documentation, a mains power cable, cable ties and screws; everything you need to get you setup and ready to rock.
A Closer Look – Exterior
The first thing you’ll notice on the PSU is a large sticker, which explains how the zero RPM fan mode operates.
With the sticker out of the way, you’ll find the unit comes with a master power switch at the back, as well as a good amount of ventilation for heat exhaust.
Around the side, the technical specifications table, and one thing I’m impressed with is a whopping 50A on the 12V rail; more than enough for a high-end gaming rig.
Around the other side, a simple SF600 branding sticker.
Around the back, you’ll find fully modular connectors. There’s a split 24-pin, two peripheral connectors, as well as three 8-pin for the motherboard and PCI-E devices.
A nice design on the top of the PSU should ensure it looks great even when inverse mounted.
Finally, we have a 92mm fan fitted with a metal grille that should provide great airflow to the interior of the PSU.
The compact size of the PSU is obviously a welcome advantage, but having fully modular cables is also going to make building your system a whole lot easier. To make things even more appealing, all of the cables are flat-type, meaning they’ll be easy to route, and they come with all black fittings, so they should easily blend into your build.
A Closer Look – Interior
The interior of the PSU is pretty amazing, as it’s packed with all the hardware you’ll want for a high-end PSU, but there’s still a rather impressive amount of space in here too. What’s immediately noticeable is the complete lack of cables, everything is neatly integrated and run through the rather busy looking PCBs, and that should really help the overall airflow.
The AC line filtering stage at the back.
The modular board design is very nicely laid out, allowing a 3D vertical layout to help keep the form factor compact as possible.
There’s a powerful 420v 470uf 105C main bulk capacitor at the side, as well as some smaller, albeit all high-quality, secondary caps for the other voltages.
The modular connector board is packed with extra caps too, which we’ve seen on many other Corsair PSUs before, so hopefully we’ll see some impressive voltage regulation and super-low ripple results in our testing.
Finally, we have the NR092L fan, a 92mm PWM model that can be run at zero RPM for silent performance.
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
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.
SFX PSUs are often a compromise on performance, but this is just unreal! The voltage regulation is simply excellent across the board.
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.
Amazingly, this Gold-rated unit is stepping more into the Platinum efficiency than it is Gold, which is obviously very good news. We saw between 93 and 94% efficiency throughout all our tests.
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 is really good here, there’s a small dip at 40% but it’s really a lot smaller than it looks, otherwise, the score is pretty high here and a lot better than we expected.
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|
Once again, Corsair absolutely dominates here, scoring exceptionally low ripple and showing that despite its compact size, this PSU can deliver clean and stable power.
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).
Not done with exceeding our expectations, the SF600 managed to pull a mighty 813W before the OPP kicked in. Naturally it’ll like get a little warm doing this all day long, but for the occasional power spike, you should have nothing to worry about.
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
The hybrid fan worked far better than we expected, with the fan staying off entirely until we passed 40% load. Even then, we had to leave the unit running for longer to give it a chance to warm up a little more, as even at 60, 80 and 100% load the fan didn’t kick in for a good few minutes and even when it did, it was far quieter than you would think given its RPM and dimensions.
The Corsair SF600 is available from Scan.co.uk for £99.98, which is obviously a bit more than most 600W units, but keep in mind that gold efficiency and the compact SFX form factor, as it’s one of the best performance and priced SFX PSUs on the market today.
Corsair has been pushing hard to make some truly spectacular power supplies recently and time and time again, they’ve delivered the goods. Their latest, the SF600, isn’t just good for an SFX PSU, it’s one of the best 600W units I’ve ever tested, and that’s something that shouldn’t be taken lightly. When you’re building a compact gaming system, size is important and an SFX PSU allows the use of a much slimmer form factor chassis. However, this used to mean a compromise on wattage, or efficiency and even then, you would be paying a price premium.
The SF600 delivers a huge amount of power for its size, more than enough to power any of the latest high-end graphics cards and a heavily overclocked CPU with relative ease. What’s impressive is that it manages to deliver all this power with exceptionally stable voltages, incredibly low ripple and even more so, it steps closer to the 80 Plus Platinum efficiency rating when it’s only rated as 80 Plus Gold; if that’s not great value for money, nothing is.
Overall, the build quality on this unit is as good as it gets. There’s not a single wire to be found on the interior of the unit, just nicely laid out PCBs that use a modular 3D design to save on space and help with airflow. The 92mm fan is excellent in terms of quality as even at higher RPM is was much quieter than we would have expected and even then, the optimised layout of the PSU means that it’s able to cool passively under lower load scenarios. The addition of fully modular all-black flat cables only helps to sweeten the deal.
- Excellent efficiency rating
- Managed to exceed watt rating by +200
- Quiet fan
- Zero RPM and silent at <40% load
- All flat cables
- Fully modular
- Low ripple and stable voltages
- Competitive price
- SFX form factor
- 7-year warranty
“Picking the right power supply for an SFX build just got a whole lot easier. If you’re looking to build a compact gaming system or workstation, the SF600 is the best option on the market right now. Highly recommended!“
Thank you Corsair for providing us with this sample.