CPUs and GPUs may be the beating heart of a gaming PC, but they are worthless without power to drive them. Choosing a power supply for your gaming PC can often be an afterthought once you spend time researching and selecting your other components, but it shouldn’t be. The power supply is responsible for delivering current to every part of your PC. If you cheap out on this critical component, you will be setting yourself up for a world of hurt.
The market is flooded with power supply choices and it can get overwhelming very quickly. While overall wattage and efficiency ratings are important, the two main features you see used to advertise PC power supplies do not tell the whole story. Ultimately, how clean and consistent the power delivery is from the unit matters the most when it comes to the high demands of PC gaming.
Selecting The Best Power Supply For Your Gaming PC
What A Power Supply Does For Your PC
In the simplest of terms, the power supply gets the power from your wall to your parts. A PC power supply will offer a 24-pin plug for your main motherboard power, an 8-pin plug for your CPU, an assortment of PCI-E power plugs for your GPU(s), plugs for SATA devices, and 5v molex plugs. High-end or high-wattage power supplies will often provide a variety of extra plugs and cables for an array of components.
If you take a quick glance at Amazon, NewEgg, or your PC parts retailer of choice, you will notice an ocean of cheap power supplies. Many of them may look like obvious fire hazards, but most will advertise high wattages and seem like they should be able to handle the job. The problem is that 500 watts from one power supply is not the same thing as 500 watts from a different power supply. Even in cases where the power supply you buy is actually capable of delivering its advertised wattage, it may not be enough for the load that your components need due to the particulars of how the manufacturer arrives at a given wattage rating.
PC power supplies generally offer power at 3 different voltages: 3v, 5v, and 12v. The power delivery system for these voltages are separate and are commonly referred to as "rails". When looking at how the total output of a PC power supply is calculated, you will have a measure of how many amps can be offered on each of the rails. The power needed by your CPU and GPU will be from the 12v rail. For example, if a random power supply advertised 500 watts, but it supplied 15 amps to the 3v rail, 15 amps to the 5v rail, and only 10 amps to the 12v rail, it will not be able to properly power your hungry CPU and GPU via the 12v rail as it only has ~120 watts of its capacity available.
Why Should You Spend More For A High-Quality Power Supply?
Another important factor to consider is the build quality of the power supply. Cheaper or poorly designed power supplies will use low-quality components. Manufacturers of such power supplies can skimp on things like capacitors, transistors, or cooling. When one of the parts of a cheap power supply fails or overheats, it not only ruins the power supply, it has the ability to drag anything connected with it down into its grave. Spending a thousand dollars on your CPU, motherboard, and GPU and then connecting them to a $25 power supply puts you at risk. Expensive PC components are usually very power hungry and will put a strain on the power supply. Once that supply croaks from the stress, you could be out of all the money you spent on your nice hardware.
Not every substandard power supply simply goes up in puff of smoke when things go wrong. An inadequate or faulty power supply can cause general system instability. This instability can manifest itself by way of application or game crashes and can even cause your gaming PC to reboot itself out of nowhere. You may build a new gaming PC and have it run well for a month or two and then begin to experience hard reboots while playing your games. Sometimes, your PC can run fine for a year, but then a demanding new release can be very unstable or cause reboots, even when none of your other games exhibit these behaviors. Nine out of ten times, these problems are the result of a poor quality or faulty power supply.
A quality power supply will offer clean, well regulated power at its rated wattage. Outstanding power supplies can deliver incredibly consistent power with minimal DC ripple. These units do so while keeping themselves cool and quiet. They will offer a healthy amount of current on the 12v rail(s), so that your CPU and GPU can get what they need. A cheaper power supply, with less stringent voltage regulation, can slowly kill your components over time with “dirty” power. It is a no-brainer to adjust your build budget to include a top-end power supply. The life of your components and peace of mind are more than worth it.
How Do I Tell Which Power Supplies Are High Quality?
Aside from choosing one of the models listed later on in this gude, there are a few resources you can use to weed out the bad apples on the power supply pile. While you may see 30 different companies selling PC power supplies, most units are built by a few different OEMs and then rebadged and resold under various brand names. There are some power supply builders who sell units under their own brand name (Seasonic), but most of what you’ll find at retail will be built by the OEMs for whatever company’s name is on the box. For this reason, you cannot simply look at a brand name and say, “All power supplies from brand XXX are great.”
Unfortunately, proper power supply reviews and testing are still rather uncommon, so beginners to building PCs don’t always have heaps of information to go on. Comprehensive reviews from sites like JohnnyGuru can be incredibly an incredibly valuable source of information, but no single outlet has the time or resources to test everything. To make sense of the confusion in finding quality power supplies, the internet PC building community worked together to classify power supplies into a tier system. You can find several of these tiered lists online. One of the most popular is hosted on the LinusTechTips forum. Tier 1 power supplies are considered to be excellent performers in all areas and are recommended with no reservations. Tier 2 power supplies are very high quality, but may not be capable of the insanely high performances and tolerances achieved by the units in Tier 1. Often, power supplies that once occupied space in Tier 1 may be bumped down to Tier 2 as new designs exceed the previous high marks set by older designs. The tiers go on down to 7, where the listed units should be avoided at all costs. If a power supply you are shopping for is not on a tier list, it may be so new that it has not yet been reviewed, or too obscure to receive inclusion.
For a gaming PC, it is strongly encouraged that you only buy from the first two tiers. These power supplies ensure years of consistent performance at or beyond their advertised specs. In situations where you may not be using a dedicated GPU or are working with the most extreme of strapped budgets, grabbing a PSU from as low as the 4th tier is acceptable. It should be noted that the tier system has no direct correlation to price. You can find affordable power supplies in each of the tiers (though you may need to wait for sales to score Tier 1 units at a great price).
Power Supply Efficiency Ratings Explained
If you’ve done any shopping for a power supply, you will have surely noticed the ratings advertised that say something like 80 Plus, followed by some precious metal like Gold or Bronze. 80 Plus is a voluntary certification program that lets manufacturers indicated the efficiency of their offerings. To be 80 Plus certified, a power supply must waste less than 20% of the power it pulls from your wall at 20, 50, and 100 percent of its rated load.
Beyond the regular 80 Plus certification, power supplies can also attain ratings that indicate efficiency beyond the standard 80 percent mark. The certifications and their required efficiencies at 20, 50 and 100 percent load are as follows:
- 80 Plus Bronze - 82% / 85% / 82%
- 80 Plus Silver - 85% / 88% / 85%
- 80 Plus Gold - 87% / 90% / 87%
- 80 Plus Platinum - 90% / 92% / 89%
- 80 Plus Titanium - 92% / 94% / 90%
As you may have noticed from the certification table, most power supplies are at their most efficient when presented with a 50% load. This leads us to the age old question…
How Many Watts Do I Need?
Because power supplies work their best when they aren’t being pushed to their absolute operating limits, it is a good idea to buy a unit that gives you some headroom when it comes to your estimated system power draw. There is no easy answer to how much wattage is needed since every PC build is different and some parts are more efficient than others. Another important consideration is if you plan on overclocking your CPU or GPU. While overclocking can be a free and relatively painless way to get more performance for your dollar, overclocked parts will draw more power. How much extra power is needed for overclocked parts varies, but the performance returns for power spent can be very costly. A 10 percent overclock on a GPU may require an additional 30 percent power draw to remain stable.
If your gaming PC is made up of entry-level performance parts and a relatively low-end GPU, you can safely select a quality 500 watt power supply and be on your way. As the performance is ramped up in part selection, the power requirements usually rise hand in hand. If you are building with the fastest parts, including a monster GPU like the NVIDIA GeForce GTX 1080 Ti, you will be better off going with a high-quality 750 watt power supply, as the 1080 Ti is known to draw over 300 watts by itself when overclocked. If you plan on using multiple GPUs, your search should begin with 850 watt and higher units, as each card will draw loads of power when in use.
Most builds will fall in between the previously mentioned extremes. Often, a high-quality 550, 600, or 650 watt power supply can be just the right fit. It never hurts to overbuy on power supply wattage, but it is not necessary. Just because you have a 1000 watt power supply does not mean it will outdraw a 500 watt power supply when hooked up to the same components, assuming both units share the same efficiency. Many of the highest-quality power supplies are capable of outperforming their rated specs and efficiencies, especially those that fall into the Tier 1 category. A 500 watt Tier 1 power supply could conceivably handle a high-end gaming PC, but you should not expect that to be true of a Tier 5 unit.
Do I Need a Modular Power Supply?
Most power supplies have all the cords hard-wired to the chassis. You will connect all of the leads that are required to use your PC, but you will often have cables that are not used, depending on your build. Modular power supplies allow you to pick and choose which cables are attached to the chassis. This can help with cable management as it can reduce unneeded clutter and possibly improve airflow in cases where an excess amount of heat could cause problems.
Modular power supplies are available in two flavors: semi-modular and full-modular. Semi-modular power supplies usually have the 24-pin ATX power cable for your motherboard hardwired to the chassis and offer ports for all the other cables. This is a common offering since virtually everyone needs the main power cable for the system anyway. Full-modular power supplies let you add or remove all cables via ports on the chassis. These units allow for the most control over your build and are the way to go if you plan on adding custom-sleeved replacement cables to add color to your build. Many custom cable companies sell full cable replacement kits that are designed to fit directly into your specific full-modular power supply.
The Best Power Supplies For Your Gaming PC
EVGA G3 Series
EVGA G2 Series
EVGA has a good thing going with its G2 and G3 lineup of power supplies. The units in these series are built for EVGA by Super Flower and represent the best bang for the buck you can get for Tier 1 power supplies. While the G2 units have been around for a couple of years, they are still amazing performers and can be had a great prices when found on sale. They feature a 10-year warranty for peace of mind. The full-modular design makes cable management a breeze.
The G3 series was introduced last year. They are slightly better in performance than the G2 units and come in slightly smaller enclosures. The smaller enclosure is great for fitting into smaller PC cases and in some of the newest models from Fractal Design that have a reduced depth. The 750 watt G3 power supply received a 9.8 (out of 10) score in its review on JohnnyGuru. In the review, it was noted that the site may have to change the way it scores performance, as the G3 is capable of operation in excess of what would usually constitute a perfect score.
Seasonic FOCUS Plus Series
Seasonic is one of the most respected power supply manufacturers on the planet. In addition to their own offerings, they make units for other brands (like the EVGA GS Series). The Seasonic FOCUS Plus series is one of the company’s best designs yet. The full-modular units come in a very small chassis and offer world-class performance for your money. You get a super-long warranty and the ever-popular Seasonic bag of goodies, including zip ties, stickers, and extra screws. You can’t forget the great drawstring power supply bag, not only does it make you feel like you are unwrapping a high-quality piece of equipment, but it is a great place to hold your weed. If choosing between the EVGA G2/G3 and the Seasonic FOCUS Plus, take the unit with the better price, as the performance difference between these Tier 1 power supplies is negligible.
Corsair RMx Series
Not to be outdone by EVGA or Seasonic, Corsair has some great power supplies in its lineup and the RMx series is up to the task of powering your gaming PC. The RMx line is built for Corsair by CWT and features Tier 1 performance in a compact chassis with a full-modular design. Like EVGA’s 750w G3 unit, the 750w RMx power supply was able to score a 9.8 over at JohnnyGuru. Many builders (and Jeff Sessions) will be happy to find that Corsair offers white variants of the RMx power supplies.
Reliable Budget Offerings
Not everyone can afford to go with top-tier equipment in all parts of their build and others will have a selection of components that simply have very light demands when it comes to power draw. For these builders, the Tier 3 Corsair CX Series power supplies make a lot of sense. While they are unable to perform as well as their more expensive RMx siblings, the CX units still offer a semi-modular design, a 5-year warranty, and nearly silent operation. The Seasonic S12II 620 gives you lots of power overhead for very little cash. This Tier 4 unit can often be found for less than $40 when on sale or with rebate. It does not have a modular cable design, but it delivers clean power on a budget and will not put you gaming PC in danger due to shoddy build quality.