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Best Power Supplies 2021

Best Power Supplies
(Image credit: Shutterstock)

Your PC's power supply / PSU plays a big role in determining your system's reliability, depending on its performance. So you should be careful when it comes to picking the right PSU for your system. The best power supply should also have features to save your system's parts (including the power supply itself), in case something goes wrong with your electricity supply or other components. If it doesn't, it's clearly not the best power supply and is putting your other expensive PC parts at risk.

You'll also have different concerns, of course, depending on whether your power supply will be pushing a monster mining rig, an always-churning workstation, or a basic productivity or gaming desktop. We’ll help you find the best power supply for your next desktop PC below.

Quick Power Supply Shopping Tips

First, figure out your wattage requirements. You don't need to purchase much more potential power capacity (wattage) than you’ll ever use. You can calculate roughly how much power your new or upgraded system will draw from the wall and look for a capacity point that satisfies your demands. Several power supply sellers have calculators that will give you a rough estimate of your system's power needs. You can find a few below:

You probably don’t need a 1,000-watt PSU, even for an extreme gaming rig. A few years ago, all graphics cards on the high-end of our GPU Benchmarks hierarchy were very power hungry. But this has changed with Nvidia's recent architectures. It's simply not necessary to buy a 1kW PSU for a couple of RTX 2080s. An 800W model will do just fine, leaving headroom for an overclocked CPU as well, as you can see in our CPU Benchmarks hierarchy. Fans of AMD's high-end Radeon VII or the newer Radeon RX 5700 XT will need to plan for higher power use, pairing these cards with PSUs featuring greater maximum output.

Check the physical dimensions of your case before buying. If you have a standard ATX PC case, chances are an ATX power supply will fit. But many higher-wattage PSUs are longer than the typical 5.5 inches. So you’ll want to be sure of your case’s PSU clearance. If you have a particularly tiny or slim PC case, it may require a less-typical (and more compact) SFX power supply. We have picks for this form factor below as well.

For more on this subject, see our A Basic Guide To Motherboard, Case and Power Supply Form Factors feature.

Want a clean build or working in a tiny case? Consider a modular power supply. If your case has lots of room behind the motherboard, or your chassis doesn’t have a window or glass side, you can of course cable-wrap the wires you don’t need and stash them inside your rig. But if the system you’re building doesn’t have space for this, or there’s no easy place to hide your cable mess, it’s worth paying extra for a modular power supply. Modular PSUs let you only plug in the power cables you need and leave the rest in the box.

The Best Power Supplies You Can Buy Today

Corsair CX450 (Image credit: Corsair)

1. Corsair CX450

Best Cheap PSU ($60/£60 or less)

Manufacturer (OEM): Channel Well Technology or Great Wall | Max. DC Output: 450W | Efficiency: 80 PLUS Bronze | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 120mm rifle bearing fan (HA1225M12F-Z or D12SM-12 ) | Modular: No | Warranty: 5 years

Low price
Full set of protection features
Great soldering quality
Rifle bearing fan
Five-year warranty
Single PCIe connector limits expansion
Not as quiet as the CWT-made CX450
Short distance between peripherals connectors

Of the two variants of Corsair's CX450, the Great Wall version is more efficient than CWT's, especially under light loads, and has a more efficient 5VSB rail. On the other side, it has a more-aggressive fan profile, so its noise output is increased. In the US market, you will only find the CWT version, which is made in Vietnam instead of China, so it avoids the tariffs and keeps its price tag low.

Read: Corsair CX450 Review

Alternate Best Cheap Power Supply: Corsair VS450

Another decent alternative if your budget is low, you need more than 500W of capacity, and you aren't that concerned about efficiency or some fan noise under load is the Corsair VS650. It won't win any performance awards, but it gets the job done without much in the way of frills or fuss, for less than $50. You may also be able to save on these or other PSUs by checking Corsair coupon codes.

Corsair RM550x

2. Corsair RM550x

Best PSU: Up to 550 Watts

Manufacturer (OEM): CWT | Max. DC Output: 550W | Efficiency: | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 135mm Rifle Bearing Fan (NR135L) | Modular: Yes | Warranty: 10 years

Full power at 48°C
Efficient
Semi-passive operation
Silent
Japanese caps
Fully modular
Expensive
No fan test button
Distance between 4-pin Molex connectors

The RM550x is an amazing PSU with fantastic ripple suppression, tight load regulation on the minor rails and excellent performance with transient loads. It’s also nearly silent, even under load. On top of that, this unit is highly efficient, although some other Gold-rated PSUs with similar capacity fare a bit better.

Another advantage of the RM550x is the quality of its internal components. The only thing that we would like to see in this PSU is a convenient way to test the fan's proper operation. The fan does spin for a short time every time the power supply is switched on, but we'd like Corsair to add a fan test button like the one on its RMi units.

Read: Corsair RM550x Review

Alternate Best PSU 550W: Phanteks AMP Series 550W

XPG Core Reactor 650W (Image credit: Tom's Hardware)

3. XPG Core Reactor 650W

Best PSU: Up to 650 Watts

Manufacturer (OEM): CWT | Max. DC Output: 650W | Efficiency: 80 PLUS Gold, ETA-A (88-91%) | Form Factor: ATX12V v2.52, EPS 2.92 | Cooling: 120mm Fluid Dynamic Bearing Fan (HA1225H12F-Z) | Modular: Fully | Warranty: 10 years

Full power at 47 degrees Celsius
High performance
Efficient
Silent operation
Good build quality
Compatible with the alternative sleep mode
Fully modular
Two EPS connectors on the same cable
The transient response at 3.3V could be better

The XPG Core Reactor with 650W max power can achieve higher overall performance than the two hottest picks in this category, the Corsair RM650x, and the Seasonic Focus Plus Gold, with similar capacity. It also has a silent operation, thanks to the relaxed fan profile, despite its compact dimensions. The build quality is high, and the provided warranty meets the competition's offerings. Finally, the two EPS connectors provide compatibility with the high-end mainboard, but they should be installed on dedicated cables—all in all, an excellent power supply.

Read: XPG Core Reactor 650W PSU Review

Alternate Best PSU 650W: Thermaltake Toughpower PF1 650W

Corsair RM750x (Image credit: Corsair)

4. Corsair RM750x

Best PSU: Up to 750 Watts

Manufacturer (OEM): CWT | Max. DC Output: 750W | Efficiency: 80 PLUS Gold, ETA-A | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 135mm Rifle Bearing Fan (NR135L) | Modular: Fully modular | Warranty: 10 years

Excellent ripple suppression
Quiet across its operating range
Solid build quality
Fully modular
2x EPS & 4x PCIe connectors
Smaller dimensions than its predecessor
10-year warranty
In-cable capacitors
Short distance between peripheral connectors
No fan-test button

The Corsair RM750x is a solid choice in this Wattage category offering, besides high performance, compact dimensions, two EPS connectors, and dead silent operation. A hefty ten-year warranty supports it, and this brand is well known for its exemplary support, should you ever need it for this PSU, since it uses a highly reliable platform. No wonder why this is among the most popular models.

Read: Corsair RM750x PSU Review

Alternate Best PSU 750W: XPG Core Reactor 750

Corsair AX850

5. Corsair AX850

Best PSU: Up to 850 Watts

(EC)Manufacturer (OEM): Seasonic | Max. DC Output: 850W | Efficiency: | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 135mm Fluid Dynamic Bearing Fan (HA13525L12F-Z) | Modular: Fully modular | Warranty: 10 years

Quiet Operation
Efficient
Great performance overall
Long hold-up time
Top build quality
Ten-year warranty
Expensive
EPS connectors should use 16AWG wires
Short distance between the peripheral connectors
High OCP on the minor rails

If you need the best 850W power supply and you don't have a restrictive budget, the AX850 should be among your top choices. It registers high performance in all areas: efficiency, load regulation, ripple suppression, transient response and, on top of that, it is dead silent as well.

While it's the best 850 watt premium PSU around, it's not a perfect device. I wish the current triggering points on the minor rails were lower, that there was a larger distance between the peripheral connectors (ideally 150mm) and that there were 16AWG gauges on the EPS connectors.

Read: Corsair AX850 Review

Alternate Best PSU 850W: XPG Core Reactor 850W

Corsair AX1000

6. Corsair AX1000

Best PSU: Up to 1250 Watts

Manufacturer (OEM): Seasonic | Max. DC Output: 1000W | Efficiency: 80 PLUS Titanium, ETA-A+ | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 135mm fluid dynamic bearing fan (HA13525M12F-Z) | Modular: Fully modular | Warranty: 10 years

80 PLUS Titanium efficiency
Solid build quality
Excellent results through our benchmark suite
Fully modular
8x PCIe &amp
2x EPS connectors
Sleeved cables
Selectable semi-passive mode
10-year warranty
Expensive
EPS connectors should use 16AWG wires
Short distance between the peripheral connectors
OCP triggering points on the minor rails should be set lower

Corsair's AX1000 is one of the best 1kW power supplies available. If you want the highest possible performance matched with quiet operation, don't hesitate to make it the centerpiece of your next build (provided the price doesn't scare you off).

This beastly PSU offers tight load regulation on all of its rails, amazing ripple suppression, and crazy-high efficiency levels. Its transient response is impressive, so we're not surprised that it takes the lead from Seasonic's 1000W 80 PLUS Platinum- and Titanium-rated models (even though they're built using the same platform with slight modifications).

Read: Corsair AX1000 Review  

Alternate Best PSU 1K Watts: Thermaltake Toughpower Grand RGB 1200W

be quiet! Dark Power Pro 12 1500W

(Image credit: be quiet!)

7. be quiet! Dark Power Pro 12 1500W

Best PSU Above 1250-1500 Watts

Manufacturer (OEM): CWT | Max. DC Output: 1500W | Efficiency: 80 PLUS Titanium, ETA-A+ | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 135mm fluid dynamic bearing fan (BQ SIW3-13525-HF) | Modular: Fully modular | Warranty: 10 years

Strong overall performance
Silent operation
Low vampire power
Lots of connectors
Expensive
Not as efficient as other PSUs in this price range

If you want silent operation and high-power output, the be quiet! Dark Power Pro 12 with 1500W max power fits the bill. It sports extremely high build quality and its semi-digital platform, offers top performance and can handle high operating temperatures. The only problem is the high price, but in systems that require this much power, the power supply is usually among the least-expensive parts when compared to the installed CPUs and GPUs. 

Read: be quiet! Dark Power Pro 12 1500W Power Supply Review

Corsair AX1600i

8. Corsair AX1600i

Best PSU Above 1500 Watts

Manufacturer (OEM): Flextronics | Max. DC Output: 1600W | Efficiency: 80 PLUS Titanium, ETA-A+ | Form Factor: ATX12V v2.4, EPS 2.92 | Cooling: 140mm Fluid Dynamic Bearing Fan (NR140P) | Modular: Fully modular | Warranty: 10 years

Full power at 48°C
Powerful &amp
efficient
Ripple suppression
Load regulation
Hold-up time
Accurate Power Ok signal
Silent
Quality caps
Fully modular
Lots of connectors
Quality fan
Magnetic side covers
Expensive
Small distance between peripheral connectors
EMI with AVG detector

We waited years for a competitor to dethrone Corsair's AX1500i, and in the end it was another Corsair power supply to post higher overall performance. The Corsair AX1600i is the best PSU that money can buy today, period. It offers top performance in all areas and uses an innovative platform, which provides a glimpse at the future of power supply design.

The use of a cutting-edge PFC circuit in combination with a fully digital platform seems to be the key for record-setting performance. Besides its super efficiency, the AX1600i also offers great load regulation, amazing transient response, a long hold-up time, and unparalleled ripple suppression. Moreover, the great benchmark results are accompanied by quiet operation, enabled by a relaxed fan profile and a high-quality FDB fan. Using the Corsair Link software, you're able to choose between three fan modes: performance, balanced, and quiet.

Read: Corsair AX1600i Review

Alternate Best PSU Above 1500 Watts:  SilverStone DA1650 Review

Corsair SF750

9. Corsair SF750

Best SFX PSU

Manufacturer (OEM): Great Wall | Max. DC Output: 750W | Efficiency: | Form Factor: SFX, EPS 2.92 | Cooling: 92mm Rifle Bearing Fan (NR092L) | Modular: Fully modular | Warranty: 10 years

Powerful
Efficient
Great ripple suppression
Tight load regulation
Quiet operation
Fully modular
7-year warranty
Expensive
Low hold-up time
Semi-passive mode can’t be deactivated

The Corsair SF750 is the strongest and one of the best SFX power supplies that money can get you today. If you want so much power out of such a small PSU and you can afford its stiff price, there is no other option. It can easily support a potent gaming system and thanks to the couple of EPS connectors that it has, and is compatible with high-end mainboards that need more juice in the CPU's area.

If you don't need more than one graphics card connector, you should consider the top-notch SF600 Platinum instead and save yourself some serious money. Corsair has set the so high in the SFX market that even SFX pioneer SilverStone, doesn't have, for the moment at least, a competing 750W SFX model in its portfolio.

Read: Corsair SF750 Review

Alternate Best SFX Power Supply: Corsair SF600 Platinum

Fractal Design Ion SFX Gold (Image credit: Fractal Design)

10. Fractal Design Ion SFX Gold

Best SFX-L PSU

Manufacturer (OEM): Seasonic | Max. DC Output: 650W | Efficiency: 80 PLUS Gold, ETA-A (88-91%) | Form Factor: SFX-L, EPS 2.92 | Cooling: 140mm FDB Fan (S1201512HB) | Modular: Fully | Warranty: 10 years

Powerful
High overall performance
SFX-to-ATX mounting bracket
Flexible and fully modular cables
Ten-year warranty
Could be quieter
Low 5VSB efficiency
High inruch current with 230V input
Some high EMI peaks at low frequencies

Fractal Design's Ion SFX (-L) model with 650W max power offers high performance, highly flexible modular cables, and compact dimensions at a reasonable price. If only its fan speed profile was a bit more relaxed.

Read: Fractal Design Ion SFX Gold Review

Alternate Best SFX-L Power Supply: SilverStone NJ450-SXL

Finding Discounts on the Best Power Supplies

Whether you're shopping for one of the best power supplies or just looking for an affordable alternative, you may find savings by checking out our lists of the latest Corsair coupon codes, Newegg promo codes and Micro Center coupons.

  • abryant
    Archived comments are found here: http://www.tomshardware.com/forum/id-3694061/psus.html
    Reply
  • DVJ Rick Kraft
    Now many motherboards require 8pin+4pin CPU power, and some even require 8pin+8pin. Since this guide is made for DIY builders, this is the most important information when buying PSUs. In your guide there should be some differentiation between limited power supplies (1x CPU 8Pin) and PSUs that are more versatile, especially since 2x CPU 8pin is required for mid-tier or higher-end motherboards.
    Reply
  • davidm.maya
    21490758 said:
    Now many motherboards require 8pin+4pin CPU power, and some even require 8pin+8pin. Since this guide is made for DIY builders, this is the most important information when buying PSUs. In your guide there should be some differentiation between limited power supplies (1x CPU 8Pin) and PSUs that are more versatile, especially since 2x CPU 8pin is required for mid-tier or higher-end motherboards.


    Yes, That's true. But I had read that the 4pin connector isn't needed if you don't do 'extreme' overclocking, I don't know how much is considered 'extreme' but at least it should be safe to connect only the 8pin for runing the CPU at stock speed.
    Reply
  • jdcranke07
    If you are running a non-k SKU of Intel processors, you probably can run with DavidM.Maya's advice. I would error on the side of caution otherwise. I also agree that the number of CPU cables with pin counts & number of SATA & Molex power cables should be in there as well. The reason you might go for a high wattage PSU like a 1600W might be for a rig that has multiple purposes, i.e. gaming rig & workstation and/or server. Peripherals such as HDDs & SSDs can determine which PSU better fits you based on cables provided.
    I have an EVGA SuperNova 1600 T2 that came with 4way SATA power cables (x2) & one cable that was 2 SATA power & 2 Molex power as an example.
    Reply