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 (Nov 28th).

Best PC Power Supplies: Holiday 2019

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.

AnandTech PC Power Supply Recommendations: 2019

(Prices are Nov-28 or MSRP) Output Range Value Option Performance Option ATX Up to 450 Watts EVGA 400 N1 $40 SeaSonic Focus SGX-450 $75 >450-600 Watts RoseWill Photon 550W $60 SeaSonic Prime Plat. 550 $110 >600-800 Watts Corsair CX750 $75 Fractal Design Ion+ 660W $110 >800-950 Watts Corsair RM850 $125 SilverStone ST80F-TI $170 1000+ Watts Cooler Master V1200 $146 SeaSonic Prime Titan. 1000 $280 SFX Up to 450 Watts SilverStone ST45SF $65 Corsair SF450 $105 >450 Watts SeaSonic Focus SGX-650 $121 Corsair SF750 $180

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.

Much like last year, 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 is becoming a little stale lately, 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 CPU and a single GPU rarely requires more than 300 Watts. A modern AMD Ryzen-based system with a single AMD RX 5500/NVIDIA GTX 1660 card will hardly reach up to 220-230 Watts, while it usually idles at 45-55 Watts. And even in a more extreme scenario - say the rather power hungry Ryzen 9 3950X paired with a GeForce RTX 2080 Ti - is going to stop short of 600W 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

< 450 Watts

SeaSonic Focus SGX-450($75)

EVGA 400 N1 ($40)

Our primary recommendation in this category lies on the EVGA 400 N1. At first sight, one might wonder why we recommend a technologically outdated design that fails to claim even the lowest of 80Plus efficiency certifications. The reason is that its simple design makes it comparatively reliable and it comes from a reputable manufacturer that backs it up with a very reasonable 2-year warranty. It retails for $40 (its price actually went up since last year), leaving us to hope for a seasonal price drop soon, as it is very difficult to find anything reliable for such a low price.

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. The SeaSonic Focus SGX-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 at a reasonable retail price of $75 (after rebate).

450 to 600 Watts

Rosewill Photon 550W ($60)

SeaSonic Prime Ultra Platinum 550 ($110)

Unlike the ostracized < 400 Watt range, there is a high demand for 450 to 600 Watt PSUs and, therefore, wider range of products available. This is a reasonable power range for a typical home entertainment / gaming PC with a single GPU card.

One of the most interesting units available in this power range is the RoseWill Photon 550W. Although RoseWill is not one of the higher profile manufacturers amongst enthusiasts, the particular model offers a fully modular design, a 5-year warranty, and comes with an 80 Plus Gold efficiency certification, all for a retail price of just $60. The only viable competition it has from a highly reputable manufacturer is from the equally powered Seasonic SSR-500GB3, which retails for $55 and is 80 Plus Bronze certified with hardwired cables.

At the other end of the spectrum, the very best PSU that money can buy in this power range is the SeaSonic Prime Ultra Platinum 550. It comes with an 80Plus Platinum efficiency certification, sports a fully modular design, has exceptional performance specifications, and is covered by a 12-year warranty. The $110 price tag is steep, but it's also more compettive than even we were expecting, with many other high-end (but not quite as good) PSUs going for a similar price.

600 to 800 Watts

Corsair CX750 ($75)

Fractal Design Ion+ Platinum 660W ($110)

Corsair HX750i ($195)

PSUs with an output between 600 and 800 Watts are very popular amongst gamers and overclockers. They provide enough capacity for serious overclocking and mods, or even for the increasingly rare dual GPU system. This power band is also popular among users that will be using just one GPU, as the power overhead provides a sense of security.

This power range is where quality low-cost products are becoming scarce. One of the few reasonably priced choices is the Corsair CX750, an 80 Plus Bronze certified PSU that comes with a 5-year long warranty. It is an aged but proven design and comes from one of the most reputable manufacturers, justifying its $75 price tag.

For users seeking high performance but do not want to break the bank, a newcomer comes with a very interesting offering this year. Fractal Design's new Ion+ series is aggressively priced, yet they offer a great set of features and come with an 80 Plus Platinum warranty. The 660W version of the Ion+ retails for $110, leaving the competition far behind in terms of value.

For those that want a very advanced product and are content with the hefty price tag, Corsair’s HX750i is the way to go. With C-Link monitoring and control, users can access a wealth of monitoring and automation features right from their desktops. It also delivers outstanding power quality figures. The only problem is that the price these days is running around $195, a very significant bump over the current retail price of the Ion+.

800 to 950 Watts

Corsair RM850 ($125)

SilverStone ST80F-TI ($170)

This power range should be reserved for users that want to power high-end dual or triple 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 unit, aesthetically pleasing, powerful, and efficient designs, with excellent power quality figures. The 850W version of the series is 80Plus Gold certified and retails for $125, a reasonable price for users who value long-term reliability and reasonable overall performance.

A surprise in this power range is the SilverStone ST80F-TI. With a power output of 800 Watts it may be not too powerful, but SilverStone is one of the very few companies that manages to sell an 80 Plus Titanium certified unit at a reasonable price. It can currently be purchased for $170, making it a great deal for users that want a standard ATX size 800W modular PSU with the highest efficiency rating.

Over 1000 Watts

Cooler Master V1200 ($146)

SeaSonic Prime Ultra Titanium 1000 ($280)

Corsair AX1600i ($460)

If you require a PSU with over 1000 Watts of output, chances are that you have at least three 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. The PSU will have to meet at least basic reliability and performance standards. One very interesting such product is Cooler Master’s V1200. It is currently retailing at $146, a price that might seem high at first, yet the PSU is 80 Plus Platinum certified and comes with a 7-year warranty. There certainly are cheaper alternatives available, but we would definitely not cheap out on the PSU when it has to power a system that costs thousands of dollars.

For users that want both great reliability and outstanding power quality, SeaSonic’s Prime 1000 Titanium is perhaps the best choice. It offers unmatched electrical performance, comes with an 80 Plus Titanium efficiency certification, and SeaSonic backs the unit up with a 12-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 $280 price tag is not unreasonable.

For users that want the absolute best and cost is not an issue, Corsair's new 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 nearly doubled since last year, currently hovering around the astronomical figure of $460.

SFX Power Supply Units

With SFX units becoming more and more popular with each passing day, 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 2019.

Up to 450 Watts

SilverStone ST45SF 450W ($65)

Corsair SF450 ($105)

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 $65, making it the ideal choice for users who want a good SFX PSU on a budget.

Corsair is a company that entered the SFX market strongly with the SF series. Their 80 Plus Gold 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 weighting its reliability and performance against its reasonable $105 price.

>450 Watts

SeaSonic Focus SGX-650 ($121)

Corsair SF750 ($180)

This power range is usually reserved for those that want to build powerful, yet compact living room gaming machines with at least one top tier graphics card installed. The more powerful SFX PSUs can handle two top tier cards nowadays, 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 venerable SeaSonic Focus SGX-650. It is one of the best SFX PSUs and the retail price tag of $121 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 supplying 750 Watts, has an 80 Plus Platinum efficiency certification, and delivers excellent power quality figures. The retail price is hefty, at $180, but we suggest nothing less for dual GPU systems.