Your PC's power supply (aka PSU) plays a significant role in determining your system's reliability, depending on its performance. So it would be best if you were careful when 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) if 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.
Of course, you'll also have different concerns depending on whether your power supply will be pushing a monster mining rig, an always-churning workstation, or a basic productivity or gaming PC. We’ll help you find the best power supply for your next desktop PC below.
Finally, one of the significant changes that the ATX12V v3.0 spec brings is the addition of a 12+4 pin PCIe connector to every PSU with more than 450W max power. This means that PSUs lacking this connector won't be compatible with new GPU generations and will soon be rendered obsolete.
Quick Power Supply Shopping Tips
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Determine 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:
- Cooler Master Power Calculator
- Seasonic Wattage Calculator
- MSI PSU Calculator
- be quiet! PSU Calculator
- Newegg PSU Calculator
Consider upcoming GPU power requirements. Although the best graphics cards are usually more power-efficient than previous generations, their power consumption increases overall. This is why the latest 12+4 pin connector that the upcoming generation graphics cards will use will provide up to 600 W of power. Currently, a pair of PCIe 6+2 pin connectors on dedicated cables are officially rated for up to 300W, and three of these connectors can deliver up to 450W safely. You should also add the up to 75W that the PCIe slot can provide in these numbers.
What troubles today's power supplies is not the maximum sustained power consumption of a GPU but its power spikes, and this is why various manufacturers suggest strong PSUs for high-end graphics cards. If the PSU's over current and over power protection features are conservatively set, the PSU can shut down once the graphics card asks for increased power, even for very short periods ( nanoseconds range). This is why EVGA offers two different OPP features in its G6 and P6 units, called firmware and hardware OPP. The first triggers at lower loads, in the millisecond range, while the latter triggers at higher loads that last for some nanoseconds. This way, short power spikes from the graphics card are addressed without shutting down the system.
If you add the increased power demands of modern high-end CPUs, you can quickly figure out why strong PSUs are necessary again. Please look at our GPU Benchmarks and CPU Benchmarks hierarchies to see how each of these chips perform relative to each other.
Check the physical dimensions of your case before buying. If you have a standard ATX case, whether or not it is one of the best PC cases, 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 cases' PSU clearance. If you have an exceptionally small 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.
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 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 is 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
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.
The smallest member of the new RMx line gets updated with a top-notch magnetic levitation fan which doesn’t affect the overall noise output, so the new RM550x is one of the quietest PSUs in the 550W category. It would be nice if Corsair added a second EPS connector in this unit, but most folks will be more than satisfied with the connection options.
Read: Corsair RM550x Review
Alternate Best PSU 550W: Phanteks AMP Series 550W
The smallest member of the new RMx line gets updated with a top-notch magnetic levitation fan which doesn’t affect the overall noise output, so the new RM550x is one of the quietest PSUs in the 550W category. It would be nice if Corsair added a second EPS connector in this unit, but most folks will be more than satisfied with the connection options.
Read: Corsair RM550x Review
Alternate Best PSU 550W: Super Flower Leadex III ARGB 550W
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
The Cooler Master V750 Gold V2 is an impressive product from an OEM that is not widely known. Actually, only Cooler Master has used this OEM, Gospower, so far. The overall performance that the V750 achieves is top of the line, managing to surpass tough opponents like the new Corsair RM750x and the EVGA SuperNOVA 750 G6. It is the first time in many years that we've seen a Cooler Master PSU topping our charts, which means that Cooler Master's power team is on the right track again.
Read: Cooler Master V750 Gold V2 PSU Review
Alternate Best PSU 750W: Corsair RM750x (2021) PSU Review
The EVGA 850 G7 is one of the best 850W units available on today's market. The Corsair RM850x (2021) is close in performance and has an advantage in noise output, while the 850 G6 loses notably in performance but achieves a significant win in noise output. The performance FSP delivered out of such a compact platform is impressive. We can't stop thinking, though, about the improvement in noise output with a larger PCB and cooling fan. Downsizing high-capacity PSUs at that degree comes at a cost, of increased noise output, under harsh conditions.
Read: EVGA SuperNOVA 850 G7 Review
Alternate Best PSU 850W: Corsair RM850x (2021) Review
MSI has a strong entry in the high-end category, with the MEG Ai1000P PCIe 5, which as its code name implies comes with a 12VHPWR connector. This is a true ATX 3.0-ready PSU, able to keep up with the demands of the new generation GPUs and most likely with the upcoming ones, too, since the RTX 4090 doesn't require an ATX 3.0 or PCIe 5.0-ready PSU to operate correctly. It just needs a powerful unit, especially if you plan to push its power limit up to 600 watts.
Read: MSI MEG Ai1000P PCIe Review
Alternate Best PSU 1000 Watts: Corsair RM1000x (2021)
The Thermaltake Toughpower GF3 1350W achieves high overall performance in almost all sections. On top of that, this PSU is ATX v3.0 and PCIe 5.0 ready, so it comes with a 12VHPWR connector out of the box, supporting NVIDIA's newest GPUs without the need for adapters. Its only downside is the excess noise, under harsh operating conditions.
Read: Thermaltake Toughpower GF3 1350W Power Supply Review
Alternate Best PSU 1250 - 1500 Watts: be quiet! Dark Power Pro 12 1500W
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
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
The SX1000 is the strongest small form factor PSU on the market today, and in reality, it is way stronger than its paper specs since we pushed it up 1480W. This is 148% above its nominal capacity! Enhance, the OEM behind this platform delivered a solid unit to SilverStone, with quite good build quality and top-notch parts.
This is also shown by the provided warranty, which at five years is pretty long, given this unit's insane power density score. In other words, the SX1000 is a small, only in dimensions, power factory, able to support everything you throw at it.
Read: SilverStone SX1000 SFX-L
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.
