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 18th).

Best PC Power Supplies: Holiday 2018

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: 2018
(Prices are Nov-18 or MSRP)
Output Range Value Option Performance Option
Up to 400 Watts EVGA 400 N1 $25 Seasonic SSP-400FL2 $130
Cougar RSB400 $50
>400-600 Watts EVGA 450 BT $40 BitFenix Whisper M 450W $70
Seasonic SSR-550PD2 $118
>600-800 Watts EVGA 650 GQ $68 Seasonic SSR-750TR $163
>800-1000 Watts Corsair TX850M $100 Corsair HX850i $130
RoseWill RBR 1000W $85 Seasonic SSR-850TR $190
Over 1000 Watts Rosewill Photon 1050W $95 Corsair AX1600i $300

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 poor performance, which will possibly be significantly worse than what a product at a fraction of the price would deliver.

We 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. Unfortunately for consumers, the number of manufacturers that are still actively competing into the market are very few and their product releases are very scarce. There are very few low-output product releases and only a couple of manufacturers have released new top-tier platforms, essentially consolidating 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 Intel Coffee Lake-based system with a single AMD RX 570/NVIDIA GTX 1060 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 Core i9 9900K 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 should 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.

< 400 Watts

Seasonic SS-400FL2($100)
Cougar RSB400 ($50)
EVGA 400 N1 ($25)

Although it is unlikely that most enthusiasts will even look at products rated at or under 400 Watts, the truth is that these are the ideal products for modern low-energy PC with a mainstream CPU and an average gaming GPU (or no GPU). Sadly, it is not a very popular segment of the market and there is little competition, meaning that there is not a very wide selection of products for the users. Meanwhile, even though the power requirements of typical household PCs are getting lower, very few manufacturers actually seem to care about widening and/or enhancing their sub-400W products range.

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, it comes from a reputable manufacturer that backs it up with a very reasonable 4-year warranty, and it retails for only $25. It is very difficult to find anything reliable for such a low price.

If you want a low-output PSU, do not want to break the bank, and yet the N1 feels too simple for you, our recommendation goes to the Cougar RSB400. It retails for double the price of the N1 but comes with an 80Plus Bronze efficiency certification, making it significantly more energy efficient and quieter than the EVGA N1. 

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. The SeaSonic SS-400FL2 is one of the very few designs with a high efficiency certification and proven electrical performance. SeaSonic developed this PSU by modifying one of their high output platforms into a completely fanless design. It is the best 400W PSU currently available but its $130 retail price is very hefty.

 

400 to 600 Watts

Seasonic SSR-550PD2($120)
BitFenix Whisper M 450W($70)
EVGA 450 BT($40)

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

This power range offers many interesting options. One of the most cost-effective products in this power range probably is the EVGA 450 BT, a PSU rated at 450 Watts and with an 80Plus Bronze certification. It has all of its cables hardwired and lacks any fancy features but retails for only $40, making it very appealing to users who only care about having a reliable, well-performing PSU.

This category offers a very large variety of PSUs, therefore we can easily recommend a product that combines high performance with good value. Our recommendation to users who want a modular PSU with a high efficiency rating goes to the 80Plus Gold certified BitFenix Whisper M 450W. Its retail price of $69 is reasonable for the kind of performance and features that this PSU offers.

Even though there are many products available in this category, very few come with very high efficiency ratings. The best PSU that money can buy in this power range probably is the SeaSonic Prime 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 only problem is its hefty $120 price tag that places out of the mainstream market.

 

600 to 800 Watts

Seasonic Prime 750 Titanium($163)
EVGA 650 GQ($68)

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 frequently creates a feeling of security.

EVGA practically dominates this power range with their 650 GQ. It is a semi-modular, 80Plus Gold certified PSU that comes with a 5-year long warranty. With a retail price of just $68, the EVGA 650 GQ is a steal, as the competition struggling to meet this price with inferior products.

For better or worse, SeaSonic dominates the top-tier segment of the market. Our recommendation for users seeking the best performance can be no other than the mythical Prime Titanium SSR-750TR PSU, the product that sets the efficiency and performance standards in the >700 Watts power range. Built to last and covered by a 12-year warranty, the only downside of the SSR-750TR is the hefty $160 price tag.

 

800 to 1000 Watts

Seasonic Prime 850 Titanium($190)
Corsair HX850i($130)
Corsair TX850M($100)
RoseWill RBR1000($85)

This power range is generally reserved for users that want to power high-end dual or triple GPU computers. 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 venerable TX series probably offers the best bang for the buck in this power range. The TX series units are very well made, aesthetically pleasing, powerful, and efficient designs. The 850W version of the series is 80Plus Gold certified and retails for just under $100, making it a reasonable choice for a powerful and reliable, yet cost-effective PSU.

Another unit that stands out in this power range is Rosewill's RBR-1000MS, which is a reasonable alternative for users seeking a very high power output but do not care about high efficiency and/or a lengthy warranty. Note that the low efficiency does not only increase the overall energy consumption of the PSU somewhat but the higher losses will inevitably make the PSU at least a little louder than a more efficient product.

As we said before, Seasonic's Prime series virtually dominates the top-tier market. The competition hardly tries to compete with Seasonic in terms of performance and is focused on the mainstream segment of the market instead. Therefore, the SSR-850TR is sort of the indisputable king when it comes to top-tier performance. The retail price of $190 is hefty, leaving room for the competition to compete in terms of value. This is where Corsair comes in with the HX850i, a PSU that lacks the 80Plus Titanium certification but makes up for it with its digital interface and much more reasonable $125 price tag.

 

Over 1000 Watts

Corsair AX1600i($300)
RoseWill Photon 1050W($95)

If you require a PSU with this kind 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 selection of a "value" PSU within this power band is a complex procedure, as the PSU has meet very high reliability standards. Thankfully, Rosewill's new Photon series combines a good set of characteristics, 80Plus Gold efficiency, and a very reasonable price tag. With its current retail price of $95, the Photon 1050W PSU is an excellent choice, as most of its power-equivalent competitors retail for 30-50% more.

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. Only SeaSonic has products that can compete with the AX1600i in terms of performance but their most powerful unit is limited to 1000 Watts, whereas Corsair's AX1600i can maintain a constant power output of 1600 Watts. There is virtually no other >1200 Watt PSU available today that combines the quality, performance, efficiency, and features of the AX1600i. The Achille's heel of the AX1600i is its astronomical retail price of $300.

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