An 850W power supply is what you need to juice up an AAA-crushing modern gaming rig if you don’t go all out with the most expensive components. The breathing room 1,000W units offer might be nice to have, but you can save yourself the cash difference if you get a quality model and don’t intend to overclock your CPU or GPU. Want the best 850W PSU for the job? Here’s what you should be looking for.
EVGA SuperNOVA 850 G7
Form factor: ATX12V | Dimensions: 150 x 85 x 130mm | Efficiency: 80+ Gold | Fan diameter: 120mm | Modular: Yes | Rail power: 120W 24A for 3.3 & 5V, 850W 80.8A for 12V, 15W 3A for 5VSB
- Excellent overall stats
- Lots of long cables
- Unique look with LED load levels
- Spacing between Molex connectors should be wider
EVGA cooperated with multiple companies throughout its G-series lifecycle, and partnering with FSP made it hit pay dirt. Despite lacking innate 12+4-pin cable compatibility, the G7 is the best 850W power supply on the market today. It excels in almost every metric and is sure to give even the most advanced system builder peace of mind.
The G7 steps its style up with an electric blue fan grille. Better yet, it has an LED load level indicator just begging for an attractive see-through case. You get an ample cable supply, including two EPS and as many PCIe cables. While all wires are sufficiently long, 100mm spacing between Molex collectors feels tight.
Speaking of tight, the G7 sports excellent voltage regulation on all rails. Its ripple suppression is also noteworthy, achieving less than 20mV differences at 100% load. Hold-up times are longer than 25ms, so landgrid instabilities won’t be a problem.
Excellent transient response settings suggest the G7 can handle abrupt changes in your system’s power needs. It’s an 80+ Gold power supply and acts like it, even exceeding the efficiency at times. The G7 doesn’t quite reach the 70% mark while idle, but that’s a negligible issue.
EVGA uses a 120mm fluid dynamic bearing fan. It keeps the G7 cool but isn’t the quietest. Not that we’d call sub-35 dB loud when the system this PSU is supposed to power likely holds more formidable fans.
Corsair RM850x (2021 Model)
Form factor: ATX12V | Dimensions: 150 x 85 x 160mm | Efficiency: 80+ Gold | Fan diameter: 140mm | Modular: Yes | Rail power: 150W 20A for 3.3 & 5V, 849.8W 70.8A for 12V, 15W 3A for 5VSB
- Excellent efficiency, especially at very low loads
- Low inrush current and ripple
- Quiet fan
- 3.3V transient response needs improving
Before the G7 came out, the updated RM850x would have been our best 850W PSU. It’s still a top choice that operates quietly and has idle efficiency like none other. Our two top picks are priced and perform similarly, making your ultimate choice a matter of personal preference.
Corsair includes three EPS cables as accessories. Strange since even the most powerful gaming motherboards only come with two 8-pin connectors. The two PCIe cables are more sensible, as is the SATA & Molex contingent. The RM850x is another PSU that would have benefited from better connector spacing, but it’s not a big deal if you don’t have lots of fans apart from each other.
We expect any PSU with an 80+ Gold rating to handle regular workloads efficiently. However, many models falter when it comes to idle power consumption. The RM850x beats the competition with more than 77% efficiency when idling. It adds up in the long run and keeps power bills down. Ripple is equally impressive, not even reaching 10mV on the 12V rail under demanding conditions.
Hold-up times are almost as long as on the G7. Conversely, Corsair’s PSU has lower insure current readings, offering better protection from abrupt surges after power outages. Voltage regulation is decent on all rails. The same goes for transient response, except for the 3.3V rail that received a downgrade from the 2018 model.
Cooling certainly didn’t get downgraded as Corsair sprang for a magnetic levitation fan. The new unit runs notably cooler, and its fan is quiet enough at sub-30dB.
be quiet! Pure Power 12 M 850W
Form factor: ATX12V | Dimensions: 150 x 85 x 160mm | Efficiency: 80+ Gold | Fan diameter: 120mm | Modular: Yes | Rail power: 120W 22A for 3.3 & 5V, 850W 70.8A for 12V, 15W 3A for 5VSB
- Adheres to the newest power & cable standards
- Runs quietly
- Excellent inrush current, hold-up time, and idle efficiency
- Loose load regulation on 12V rails
The best 850W power supply lets you build a system around an RTX 4080, so you’ll likely want one with modern cabling that supports NVidia’s best GPUs. The Pure Power family’s newest member comes with a 12+4-pin cable, lives up to its manufacturer’s name, and isn’t too expensive either.
While visually forgettable, the 12 M stands out due to ATX12V 3.0 compliance and the aforementioned proprietary cable. Traditional wires are long and varied. More than two Molex connectors would be better for airflow-focused cases, but at least they aren’t cramped.
High hold-up time and the second-lowest inrush current on the list are the 12 M’s highlights. It’s also the only PSU to come close to the RM850x’s exceptional low-load efficiency. Transient response is so-so at low usage but stabilizes past 50%, so giving your GPU an extra kick when transitioning from simpler to more complex scenes won’t cause instabilities.
Ripple suppression is average, with the highest deviation in the low 20mV range. This is far from the recommended spec, let alone damaging, so the capacitors will last longer than the PSU’s 10-year warranty. Load regulation is adequate on the minor rails but passes the 1% mark on the two 12V ones.
Unsurprisingly, a ribbed Pure Wings 2 fan handles air exhaust. It’s the quietest so far, barely clocking in at 25 dB. Size and low RPM don’t hold its effectiveness back, though.
FSP Dagger Pro 850W
Form factor: SFX | Dimensions: 125 x 65 x 100mm | Efficiency: 80+ Gold | Fan diameter: 92mm | Modular: Yes | Rail power: 120W 20A for 3.3 & 5V, 850W 70.8A for 12V, 15W 3A for 5VSB
- Fits both small and regular cases
- Long cables where it counts
- Good overall efficiency and voltage regulation
- Mediocre transient response
- Loud fan
As power demands rise, outfitting small cases with even smaller yet mighty power supplies is becoming more popular. The Dagger Pro is one such unit in a market with little competition. It wouldn’t be best 850W PSU material in the ATX12V space, but it’s not a bad option either.
The SFX format presents several challenges, most of which the Dagger overcomes. We were particularly impressed with its longer-than-average power and EPS cables. Combined with a handy ATX bracket, these let you mount the PSU inside a regular enclosure and still reach the motherboard without issue. Other wires are shorter and flat, so there’s no fear of clutter and snagging.
The technical portion of our description reveals mixed results. Voltage regulation is among the better ones on the list, with only the 5VSB rail standing out negatively. Efficiency is in line with the supply’s certificate and even better than 92% at some intervals. Idle power consumption is so-so, but other SFX models don’t fare better either.
Inrush current and hold-up time are adequate. While well within the lower third of prescribed limits, ripple suppression is higher than on our other units. Keep in mind that SFX models don’t have as much room for capacitors, so the results are in line with expectations.
The transient response is mediocre on all rails. This can potentially decrease the PSU’s longevity and might lead to higher temperatures. The 92mm fan keeps those in check despite its size. It has to spin faster to compensate, which makes this the loudest 850W PSU on the list.
XPG Core Reactor 850W
Form factor: ATX12V | Dimensions: 150 x 85 x 140mm | Efficiency: 80+ Gold | Fan diameter: 120mm | Modular: Yes | Rail power: 120W 22A for 3.3 & 5V, 850W 70.8A for 12V, 15W 3A for 5VSB
- Plenty of cables that are easy to build with
- Great efficiency and low inrush current
- Above-average ripple suppression
- Lax 12V rail voltage regulation
Our last entry might sound like it should power a starship, but it’s actually the best 850W PSU for anyone with a smaller budget than our top picks allow. XPG has constructed an overall excellent power supply with a few minor snags, so it’s worth checking out if you want to save $20 – $30 over our top picks.
XPG wasn’t stingy with accessories since you get two EPS and PCIe cables. The latter have two connections each, more than enough for your GPU and a capture card to boot. Only the ones responsible for feeding power to demanding components are thicker, so management inside your case shouldn’t be hard.
The Core Reactor is another power supply that steps up to the low-power efficiency challenge. Coupled with 80+ Gold values throughout, it ensures you’re pulling barely more power from the wall than your PC is using. It’s also the model with the lowest inrush current we’ve come across so far.
Other than a wider deviation on the 3.3V rail, the Core reactor keeps the transient response tight. It has above-average hold-up time, and ripple suppression is second only to the G7’s. The double-ball bearing fan is tough enough to withstand higher temperatures than rifle-bearing alternatives. Its loudness averages around 30dB – an OK result.
Mediocre voltage regulation on the main rail is what keeps the Core Reactor from climbing higher. Ideally, 12V rail voltage differences shouldn’t reach more than 1% across a PSU’s wattage range. Here, it’s at 1.5%. While that still adheres to modern safety standards, it means the Core Reactor places more stress on connected components than other models.