Corsair SF1000 ATX 3.1 PCIe 5.0 Platinum Power Supply Review

Corsair has somehow managed to stay at the top of the market for a very long time now, with many of the most popular and best products in multiple categories, with incredible gaming monitors, desks, chairs, keyboards, mice, headsets, SSDs, power supplies, coolers, cameras, and so much more. There's no sign of them slowing down either, actually, quite the opposite, as we saw at Computex 2024, they've got a lot of new stuff on the way. One of their most exciting new products, however, is their ATX 3.1 and PCIe 5.1 certified 80 Plus Platinum power supply, which can deliver incredible efficiency, 1000w of power, and all in a very compact true-SFX form factor. SFX PSUs are getting incredibly powerful these days, and having 1000W in SFX is simply amazing, especially with both 80 Plus Platinum and Cybernetics Platinum certification, fully modular cables, a zero RPM fan mode below 400 watts, and 12VHPWR support; you really couldn't ask for much more from a power supply than what's on offer here. Features of the Toughpower SFX Series 80 PLUS Platinum rated efficiency ATX 3.1 compliant, supporting PCIe 5.1 Fully modular, Type-5 Micro-Fit PSU connectors 92mm PWM cooling fan with Zero RPM mode For further specifications, please check out the official product page here. What Corsair Had to Say The ATX 3.1 standard demands a high level of reliability and power efficiency. While many CORSAIR PSUs meet these requirements, SF Series PSUs are formally certified for ATX 3.1 compliance. PCIe 5.1 12VHPWR GPU cable included for use with modern graphics cards such as the NVIDIA® GeForce RTX™ 40 Series. Packaging & Accessories The box is classic Corsair, with that striking yellow and black design and a large and clear photo of the power supply right on the front, as well as badges for the 7 year warranty, and ATX and PCIe certifications, and Platinum efficiency. Around the back, things get a bit technical, with a run down of all the key features, efficiency curve, fan noise levels, and the capabilities of each of the voltage rails. The PSU is well packaged, with a separate section for all of all of the modular cables, but unfortunately, not protective bag to store unused cables in. All of the cables are of a good quality, and feature black cables with black headers, and a flat cable design that should benefit your cable management. A Closer Look I think the most impressive thing about this PSU is the size, as delivering 1000W in an SFX form factor is pretty incredible. Admittedly, Corsair aren't holding an exclusive on this output and form factor, why only recently we reviewed one from Thermaltake. However, that doesn't change how technically impressive it is to get 1000W in a power supply you can hold in one hand. Interestingly, I have the SF750W at my disposal today too, and as you can see, that's the same size as the 1000W. SFX PSUs are fantastic for SFF and mini-ITX PC builds, but at 1000W, you can still cram in any flagship GPU and CPU combo with absolutely no compromise on power delivery and performance. The PSU is equipped with a 92mm PWM fan, which has ample ventilation on the top. There's a good amount of ventilation at the back too, allowing heat to easy be exhausted from the PSU. However, at Platinum efficiency, it's unlikely this PSU will generate much heat anyway. There's also a master power switch and the AC line-in here too. As you can see, the PSU is fully modular, and that's true of both the 750W and the 850W models too. There's a native 12VHPWR connector too, allowing for a single PSU cable connection to the latest graphics cards such as the RTX 40-series. Overall, the outward design is clean and tidy, but still has the same design DNA we've seen across countless Corsair PSUs, cases, coolers and other products in recent years, so it's sure to look great along side other Corsair products in your build. A Closer Look - Interior The Corsair SF series PSU all use a good quality 92mm fan for cooling, obviously that's a fairly small fan, but keep in mind, these are very small power supplies, so 92mm is the upper limit of what will fit. That being said, because they're designed to be so efficient, they're not going to generate as much waste heat as an 80 Plus Gold or 80 Plus Bronze PSU would. What's really striking, however, is just how clean the interior of the PSU is. It's one of the smartest looking layouts I've seen, especially given just how much hardware Corsair has crammed into such a small space. There's a very robust level of shielding around the AC line-in, and that's true of a lot of the components too, likely needed given their close proximity. The coils are neat and tidy, with two smaller ones on the side here for the DC-DC 5v and 3.3v conversion. And some larger ones towards the rear as part of the PFC. There's a black aluminium heatsink right down the middle, with multiple fins split into multiple sections keeping the MOSFETs cool. Even the main transformer has a bit of Corsair branding and looks nicer than what we usually see, not that it needs to, but I like the attention to detail here. The main bulk capacitor is pretty chunky, and just like all the other capacitors in this PSU, they're all Japanese made and rated for 105c operation. Everything is pristine in here, even the back board for the connectors, and I'd say it's pretty obvious it's all machine soldered, as it's all extremely clean and uniform throughout. Methodology & Testing 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 can 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. Testing Hardware Sunmoon SM-8800 Active Load Tester Stingray DS1M12 USB Oscilloscope Voltcraft DT-10L laser tachometer What the eTeknix Test Procedure Involves Testing each power supply at 20/40/60/80/100% load (with load balanced across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power "pulled at the wall") which also uses a 50% load test, 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. Transient loads taken with an oscilloscope are taken from 0% to 100% on the 12v raid, 3.3v rail, and then both combined. Measuring fan speed after a stabilisation period of five minutes at each loading 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. Any deviation from this will be explained per review as appropriate on the respective testing pages, but this methodology page will remain unchanged. Other Things to Consider We recognise that a single 12-volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) so we used an adequate number of cables for each power supply to ensure there is no efficiency loss from poor cable selection. If there is more than one 12VHPWR on a PSU, all will be used to test their combined loads. 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 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 deviation of each rail from its expected voltage. Ideally, anything of +/- 2% regulation is seen as a very good result. Power Efficiency Power efficiency is measured by calculating the 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 power supplies at 230v. Transient Loads Power Factor Correction Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. PFC aims 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). Ripple An oscilloscope can easily measure noise and Ripple. 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. OPP Power supplies are often quoted as having various protection mechanisms 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 before it blew up. 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 of the noise. The ambient temperature during testing is held constant at 22 degrees, with 1 degree of variation. Each power supply had a consistent 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 - 2000 RPM or above - Intolerable Internal Components This is just an example of what you can expect to see on a PSU interior. Efficiency Unsurprisingly, the efficiency is excellent, as this is a platinum rated unit, but even more impressive is that it's still pretty high even by that standard, having better efficiency than a lot of full-size ATX platinum units. PFC (Power Factor Correction) This is reflected in the PFC too, which scored strong throughout, but really hit its stride from 60% load upwards, with very little power factor correction, resulting in better efficiency and less waste heat generation. Voltage Regulation Voltage regulation is also superb, scoring just -0.72% to 1.42%, and well within the +/- 3% we want to see on a good quality power supply. Ripple Again, fantastic results here, with extremely low noise and ripple on every rail, becoming even better as power input increases, and that means good system health and stability throughout all use cases. 3.3V 5V 12V Over Power Protection and Max Wattage A 1000W is impressive, but that main bulk capacitor was an absolute unit, one of the biggest I've ever seen, despite this being a small PSU. I was able to pull nearly 50% more power before the PSU turned its self off, so dealing with power spikes certainly won't be an issue. Cross-Loads Cross loads are looking just as stable as expected based on the voltage regulation and ripple results we've seen so far, with tolerances well within our ideal 3% targets. Fan Speed Despite being so powerful and compact, this PSU can actually run passively up to around 400W or until the thermal limits kick in, which may be sooner on a really hot day. However, even when the fan is going, the incredible efficiency makes cooling pretty easy, and the fan didn't have to work hard under prolonged high load. How Much Does it Cost? Honestly, I thought this PSU was going to be much more expensive than it is. However, at just £199.99 for a 1000w, ultra-compact SFX power supply, with 80 Plus Platinum efficiency, fully-modular individually sleeved cables, and all the latest features you could ask for, I really think its a big of a bargain. Especially when the ASUS ROG LOKI is SFX-L (bigger) and costs around £60 more. Overview This is one of the easier conclusions I've ever had to write, as it's an absolutely flawless product that excels in every aspect, and comes surprisingly reasonably priced. To deliver such massive power in such a small form factor is impressive in its self. However, the SF1000 is so robust and over built, it was able to draw nearly 1500W for a short period of time, which is truly bonkers for something so small. However, the big power is one thing, getting that power and delivering it with some of the best ripple and voltage regulation of any PSU I've tested is another. Often, SFX PSUs come with a compromise, be that a silly price tag, lower power, a noisy fan, they get hot, or something like that, but the SF1000W is getting a thumbs up in every respect. While Corsair aren't the only ones using them, I love the mini PSU connectors on the cables, it really saves a lot of unwanted bulk and keeps the form factor from being artificially longer due to bulky connectors. Adding fully sleeved cables is a nice touch too, it makes everything just look a bit nicer. Should I Buy One? 1000W of power in the SFX form factor, with absolutely stellar power delivery, the SF1000 is a fantastic power supply that's sure to please any PC enthusiast wanting to power the latest and greatest combos of CPU and GPU in a SFF PC build.