Best PC Power Supplies: Holiday 2020

In our series of holiday buyer's guides, here's the latest update to our recommended power supplies list. All numbers in the text are updated to reflect pricing at the time of writing.

Best PC Power Supplies: Holiday 2020

Now that you've picked out your CPU, it's time to start picking out the rest of your system components. And perhaps the most humble but overlooked of these components is the power supply unit (PSU). Available in a wide range of sizes and power capacities, there are a number of great PSUs out there, but choosing between them can be a challenge. So today we're bringing you our annual PC power supply guide, to help you sort figure out what the best options are, be it a low-wattage unit for a small form factor PC, or a hulking kilowatt unit for the most powerful PC.

When shopping for a PSU, it is very important to be aware of your system’s power consumption and to consider any planned upgrades. All current computer PSUs are designed to deliver optimal performance at (or almost at) half load. Conversely however, it is a common misconception that a more powerful PSU will be a better choice, as the power quality and efficiency of all modern PSUs dwindles at very low loads. This is especially true at the low-end of the loading curve, usually below 15% of the unit's rated capacity, where efficiency outright plummets. In fact, only the 80Plus Titanium guidelines dictate a low-load standard, and that's an efficiency requirement of 90% at 10% load. Therefore, the choice of a too powerful PSU will result in poorer performance, which can be significantly worse than what a properly-sized product at a fraction of the price would deliver.

Overall, we've split our recommendations into five main wattage categories with at least two units for each. One selection will be based on the maximum possible value (e.g. bang for the buck) and one will focus on the best overall performance.

Looking broadly at the market for power supplies, PSU technology has been a bit stale as of late, as manufacturers are struggling to meaningfully improve their designs without driving up their costs. As PSUs have become very efficient and are now employing advanced design topologies, any further upgrades rely heavily on materials science, such as employing relatively expensive Gallium Nitride-based parts. Short of that, there's a practical limit to how much an existing design can be upgraded by using better parts without making it too expensive for a price-sensitive market, which is why PSU designs have been advancing very slowly over the past few years.

Ultimately, in the last year there have been very few low-output product releases, and only a couple of manufacturers have released new top-tier platforms, essentially monopolizing the high-end market. The following paragraphs expand on the proper selection of a PSU and details on why these units are our recommendations.

How Much Power Do I Really Need?

Overall, the best way to select a PSU is based on both objective (e.g. wattage, performance) and subjective (e.g. design, modular cables) parameters. This admittedly does require every builder to be capable of making at least an educated guess about the power requirements of the system. However, this is where our guide and advice come in.

Perhaps the biggest mistake that many users make in selecting PSUs is overrating the power requirements of their systems. It is not uncommon for people – even store salespersons and experienced builders – to recommend a 1kW unit to a user with just two (or even one) high performance GPUs. A system with a single mainstream CPU and a matching video card rarely requires more than 350 Watts. A modern AMD Ryzen-based system with a single AMD RX 5500/NVIDIA GTX 1660 card will hardly reach up to 225 Watts, while it usually idles at 45-55 Watts. And even in a more extreme scenario - say the rather power hungry Ryzen 9 5950X paired with a GeForce RTX 3090 - is going to stop short of 650W even in pathological loads.

Meanwhile "wattage calculators", though an improvement from blindly guessing, are usually simple tools that get their numbers from the design power (TDP) specifications of components. The TDP of a component does not represent the actual power requirements of a component -  it's at best a broad guideline - and it also is next to impossible to place every single component of a system under maximum stress simultaneously. However, keep in mind that a PSU needs to operate at around half load for optimal performance. With that in mind, while the recommendations of the online tools and calculators may be overestimated, they're not overly so. Selecting a unit of the wattage they recommend is not usually a bad idea, as the recommendation usually is twice the actual power requirements of the system. The common mistake is that users usually seek to buy a significantly more powerful unit, thinking that having extra power helps, and end up with a severely oversized PSU for their system that will be both more expensive to purchase and unable to perform as it should.

If you can measure the actual power requirements of your system, keep in mind that you should not buy a unit that will frequently operate near its maximum capacity. Just as you would not run your car constantly near the red line, a PSU should not be under maximum stress for prolonged periods. A high quality PSU can withstand it, but just because it can does not mean it should. Again, all switching PSUs deliver their maximum efficiency at roughly 50% of their rated capacity. Running a PSU at over 90% capacity for prolonged periods of time will not only reduce its performance but it will also make it hotter, louder, and decrease its expected lifespan.

ATX Power Supply Units

Up To 450 Watts

EVGA 400 N1 ($40)
Seasonic Prime PX-450 ($135)

Our primary recommendation in this category lies on the EVGA 400 N1.  At first sight, one may ask why we suggest a technologically aged model that struggles to assert even the lowest of 80Plus certifications. The reason for this is that its simple design makes it relatively reliable and that it comes from a reputable manufacturer that supports it with a reasonable 2-year warranty. It currently retails for $40 – the same price as last year – and suffice it to say, it is very difficult to find anything reliable for such a low price.

At the other end of the spectrum, there are very few high-performance PSUs in this power range, greatly limiting our potential recommendations. One quick search is enough to indicate that PSUs with high efficiency ratings are practically non-existent in this power range, as manufacturers do not want to focus their R&D on products that benefit little from having high efficiency ratings.

Among the handful of candidates here, the Seasonic Prime PX-450 is one of the very few designs with a high efficiency certification, proven electrical performance, great quality, and a lengthy warranty. It is, in our opinion, the best 450W PSU currently available. The only downside here is that the retail price of $135 is ludicrous, even for an 80Plus Platinum certified unit.

500 to 600 Watts

SilverStone ET550-B ($56)
Seasonic Focus GX-550 ($90)
SilverStone Strider ST550F-PT ($110)

Unlike the underserved sub-500 Watt range, there is a high demand for 500 to 600 Watt PSUs and, therefore, a wider range of products available. This is a reasonable power range for a typical home entertainment / gaming PC with a single mainstream video card.

Perhaps the most cost-effective choice in this power range comes from SilverStone this year, with their ET550-B unit currently retailing for $56. The 80Plus Bronze efficiency rating is not impressive nowadays but it is a good all-rounder with a 3-year warranty.

Taking a large step up in efficiency and performance while still taking cost into consideration, Seasonic’s Focus GM-550 probably is the most well-balanced high performance PSU in this power range. With an 80Plus Gold efficiency certification, stellar electrical performance, semi-modular cabling, and a 7-year warranty, the retail price of $90 is more than reasonable.

If you want even more, SilverStone has you covered with the Strider ST550F-PT, an 80Plus Platinum and modular PSU, but the retail price increases to $110.

650 to 800 Watts

Cougar CMX700 ($80)
Fractal Design Ion+ 760W ($150)

PSUs with an output between 600 and 800 Watts are very popular amongst gamers and overclockers. They provide enough capacity for high-end components like 16 core processors and 350 Watt video cards, and offer a lot of headroom for overclocking as well. This power band tends to be popular overall, as the power overhead provides a sense of security.

There are few quality low-cost products in this power range, as most companies focus their efforts on developing fancy and/or high performance units. One reasonably priced choice is Cougar’s CMX700, an 80Plus Bronze certified PSU that is based on an old, yet proven platform. With a price tag of $80, it is one of the very few proven products in this power range that retails for less than $100.

For those seeking top-tier performance in this power range, Fractal Design has them covered with the 760-Watt version of their Ion+. The Ion+ has an 80Plus Platinum efficiency certification while it offers excellent electrical performance, a fully modular design, and a ludicrous 10-year warranty. Its retail price of $150 is steep but competitive after considering its features and performance.

850 to 950 Watts

Corsair RM850 ($135)
Corsair AX850 ($245)

This power range is typically reserved for users that want to power increasingly workstation-focused multi-GPU computers. Low cost alternatives from reputable manufacturers here are becoming scarce - we cannot go very cheap in this power range because we believe that long-term reliability is an absolute must whether we are considering a high-end gaming system or a professional workstation.

Corsair's RM series probably offers the best bang for the buck in this power range, despite their seemingly high retail price. They are very well-made, aesthetically pleasing, powerful, and efficient designs, with excellent power quality figures. The 850W version of the series is 80Plus Gold certified and retails for $135, a reasonable price for users who value long-term reliability and reasonable overall performance.

For those that want something significantly better than the RM850, Corsair has them covered with their top-tier AX series and the AX850. The AX850 is a far superior design, with an 80Plus Titanium certification, stellar electrical performance, and a 10-year warranty. The only downside here is the painful $245 retail price – more than $100 over the price of the mid-tier RM850.

Over 1000 Watts

Rosewill Glacier 100W ($130)
SilverStone Strider ST1200-PT ($245)
Corsair AX1000 ($285)

If you require a PSU with over 1000 Watts of output, chances are that you have at least a couple of high-end GPUs and/or a seriously powerful dual-CPU system with a lot of devices. These PSUs also find use in advanced servers and cryptocurrency mining systems. That being said, the PSU is going to be powering a rather expensive system, the function of which is frequently very important.

Considering the above, the definition of a "value" PSU within this power band is rather vague. Any such PSU will have to meet at least basic reliability and performance standards. One such product is Rosewill's Glacier 1000W. It is currently retailing at $130, a not unreasonable price for an 80Plus Bronze tier PSU with this kind of capacity and a three year warranty.

Still, given the kind of expensive systems that a 1000W+ unit would end up powering, it's not a bad idea to go with a higher efficiency PSU – small losses aren't quite so small at 1kW – as well as to snag something built to a higher standard of quality overall. The only catch is that moving to something significantly better than the Glacier nearly doubles the cost, which has a further side-effect of placing most high-performance units roughly around the same price point. For example, the currently cheapest 80Plus Platinum certified unit that we would recommend is the SilverStone Strider ST1200-PT, which currently retails for $240 – over $100 more than the Glacier, but only $30-50 less than top-tier alternatives.

For users that want both great reliability and outstanding power quality, Corsair’s AX1000 is the best choice available today without breaking the bank. It offers unmatched electrical performance, comes with an 80 Plus Titanium efficiency certification, and Corsair backs the unit up with a 10-year warranty. It is a product that will possibly outlive several generations of CPUs before it needs to be retired itself, which is why the $285 price tag is not unreasonable.

Otherwise, for users that want the absolute best and cost is not an issue, Corsair's AX1600i undeniably is the performance champion in the >1200 Watts power range. There is virtually no other >1200 Watt PSU available today that combines the quality, performance, efficiency, and features of the AX1600i. The problem here is that the retail price of the AX1600i doubled since its release two years ago, currently hovering around the astronomical figure of $580.

SFX Power Supply Units

With SFX units becoming more and more popular with each passing generation, it is only fair that we should include them into this year’s PSU buyer guide. There are still but a few reputable contenders in the SFX market, yet there is healthy competition, with several advanced units becoming available in recent years.

Up to 450 Watts

SilverStone ST45SF ($85)
Corsair SF450 Platinum ($125)

This power range should reflect the needs of most users building standard SFX-based entertainment systems. 350-450 Watts are more than enough for an efficient system, even if it has a mainstream range graphics card installed.

SilverStone is a traditional and major player in the SFX market. After all, the company is strongly focused on the design and marketing of SFX cases, so it is only reasonable that they would spend a lot of R&D on SFX PSUs as well. SilverStone offers a lot of SFX units, ranging from very basic products to the farfetched SX800 800W PSU, yet the product that we believe it stands out is one of their basic models, the ST45SF. The SilverStone ST45SF is a standard SFX-sized 450W PSU with an 80 Plus Bronze certification and a retail price of $85, making it the best choice for users who want a good SFX PSU at a reasonable price.

Meanwhile we also have Corsair, a company that made a strong entrance into the SFX market with the SF series. The new version of the SF450 boasts 80 Plus Platinum efficiency certification, modular design, good power quality, and reasonable price tag are giving the competition a hard time. The SF450 is probably one of the best choices for a 450W SFX PSU when weighing its reliability and performance against its passable $125 price.

500+ Watts

SilverStone SX650-G ($126)
Corsair SF750 ($185)

SFX units over 450 Watts are usually reserved for those that want to build powerful-yet-compact living room gaming machines with at least one high-end graphics card installed. The more powerful SFX PSUs can handle even the most power hungry video card these days, making the build of such gaming machines an expensive but possible endeavor.

Alas, there are no cheap options when one wants a powerful SFX PSU. The least expensive PSU that we would recommend to users that expect to power a top tier graphics card with it is the SilverStone SX650-G. SilverStone is a veteran when it comes to developing high performance SFX PSUs and the retail price tag of $126 is reasonable considering where the competition stands.

For those seeking something even more powerful, Corsair comes to the rescue with the SF750. It is capable of outputting 750 Watts while it retains its SFX form factor, has an 80 Plus Platinum efficiency certification, and delivers excellent power quality figures. The retail price is hefty, at $185, but we suggest nothing less for dual GPU systems.