When you’re putting together a gaming PC, one of the key components is the power supply. You need to carefully plan which power supply you’ll need in order to provide enough power to your whole system, otherwise it won’t work.
But while power supplies are rated for their maximum wattage, they also have another rating – or at least most of them do. This is the 80 Plus rating and it tells you just how efficient your power supply is.
If you’re wondering exactly what that means – and why you should care – then this article has all the answers.
What does a power supply do?
A gaming PC is made up of many different parts, all of which are connected to the motherboard in some way. But each component needs electricity to work, and some of them need a lot more than others.
Motherboards do have multiple power connectors, which are designed to deliver power to some of the different parts. You’ll have a main connector for the motherboard, but a separate one for the processor for example.
And then your graphics card will have its own port for power too, while some hard drives, SSDs, and DVD drives may also need their own power cable.
You can hardly run a cable for each of these different ports straight into the mains, which is why PCs have a power supply. These are boxes that are designed to manage the flow of electricity into your PC. They plug into the mains via a single cable and then split the power through various cables to the different parts of the PC that need it.
They also do the important job of changing the Alternating Current (AC) of your mains power into a Direct Current (DC) flow of electricity. PCs won’t work on an AC flow, which is why the power supply is so important.
What is power supply efficiency?
Whenever there’s a transfer of energy – like there is when converting an AC current into DC power for your PC – there’s never going to be 100% efficiency. You’re going to lose some power in the process.
This means that, if your PC requires 500 watts of power in order to run, your power supply is going to have to draw slightly more than that from the mains, because it will lose some wattage in the conversion process.
‘Efficiency’ refers to how much power is lost. The more efficient a power supply, the less energy it wastes during this process. Ideally, if your PC only needs 500 watts to run, you want to be drawing as close to 500 watts as possible from the mains, rather than drawing a lot more that’s just being used up for no good reason.
This is really important with gaming PCs because efficiency is measured in percentages, so a power supply may use 10% more power than the PC requires, or 20%, or even potentially more. Since a gaming PC uses a lot more power than a regular PC, any inefficient power supply is going to waste a lot more electricity.
Say, for example, you have an office PC that uses 250 watts of power, and a power supply that requires an extra 10% of power – that’s 25 watts extra that you’re drawing from the wall.
But if that was a gaming PC that needs 600 watts of power, the same power supply that needs an extra 10% of power is now drawing an extra 60 watts. That’s 35 extra watts being wasted, which over time will add up to a lot of wasted electricity.
That’s why you definitely need to be looking out for an efficient power supply when you put together a gaming PC.
What are the power supply efficiency ratings?
You might be wondering how on earth you’re supposed to know which power supplies are efficient. Thankfully, it’s made a lot easier thanks to the ‘80 Plus’ stamp, which refers to the power supply efficient rating.
This is an award given to power supplies that meet a certain minimum requirement of efficiency – specifically, they are at least 80% efficient when they are at 20% load, 50% load, and 100% load.
When we’re talking about load, we mean how much electricity out of the power supply’s capacity it is being asked to draw. So with a 600-watt power supply, 20% load is when a PC is trying to draw 120 watts, 50% load is when a PC is trying to draw 300 watts, and 100% load is when a PC is trying to draw 600 watts.
And when we talk about 80% efficiency, we mean that the PC is using at least 80% of drawn power from the mains to provide to the PC.
So, if a PC requires 500 watts of power, a power supply running at 80% efficiency will draw 625 watts of power from the mains, because 80% of 625 watts = 500 watts, which is what the PC needs.
The higher the percentages, the less extra power is being drawn. And there are 6 stamps of approval given to some power supplies that show that they are at least 80% efficient at those three standard loads.
These are:
- 80 Plus
- 80 Plus Bronze
- 80 Plus Silver
- 80 Plus Gold
- 80 Plus Platinum
- 80 Plus Titanium
How they are granted is based on their minimum efficiency at each load. Here’s a breakdown:
| Load | 80 Plus | 80 Plus Bronze | 80 Plus Silver | 80 Plus Gold | 80 Plus Platinum | 80 Plus Titanium |
|---|---|---|---|---|---|---|
| 20% | 80% | 82% | 85% | 87% | 90% | 90% |
| 50% | 80% | 85% | 88% | 90% | 92% | 92% |
| 100% | 80% | 82% | 85% | 87% | 89% | 94% |
The better a power supply, the less excess energy it needs. What’s interesting to note is that, in almost all cases, a power supply is more efficient when put under 50% load. The only exception is the 80 Plus Titanium which is most efficient at 100% capacity.
Are all power supplies rated 80 Plus?
Not all power supplies even make the 80 Plus grade, so it’s really important you check the efficiency before you buy. If a power supply isn’t rated at least 80 Plus then you’ve no idea how efficient it is, as it could be anything below 80%.
What PSU rating should I get?
The recommendation is that you shouldn’t buy anything less than an 80 Plus Bronze if you’re putting together a gaming PC, but aim as high as you can comfortably afford.
80 Plus Titanium is normally considered unnecessary due to how expensive they are, but if you have a good budget then you may be able to afford an 80 Plus Platinum supply.
80 Plus Silver aren’t as common anymore, with 80 Plus Bronze and 80 Plus Gold being the most common power supplies you’ll find.
How much electricity does an efficient power supply save?
Let’s get into the specifics more and look at exactly how much electricity a power supply saves you using two example PCs.
The first is a budget PC that isn’t running the most powerful spec, and so has an assumed total power requirement of 300 watts. The second is a high-end PC that requires around 600 watts of power on average.
Budget PC
For the budget PC, let’s compare a 350-watt power supply that will be running at almost 100% load, against a 700-watt power supply that will be running at 50% load, since we know that will likely be more efficient. We’ll compare Bronze Vs Gold PSU for these examples.
| PC power draw | Power supply | Estimated efficiency | Total average power draw | Average electricity cost per kWh | Cost to run per hour | Cost to run per day (8 hours) | Cost to run per year |
|---|---|---|---|---|---|---|---|
| 300 watts | 350-watt 80 Plus Bronze | 82% | 366 watts | $0.14 | $0.051 | $0.41 | $148.92 |
| 300 watts | 350-watt 80 Plus Gold | 87% | 345 watts | $0.14 | $0.048 | $0.38 | $138.70 |
| 300 watts | 700-watt 80 Plus Bronze | 85% | 353 watts | $0.14 | $0.049 | $0.39 | $142.35 |
| 300 watts | 700-watt 80 Plus Gold | 90% | 333 watts | $0.14 | $0.047 | $0.37 | $135.05 |
As you can tell, the 700-watt 80 Plus Gold is, unsurprisingly, the most efficient and compared with a 350-watt 80 Plus Bronze, it could save you $13 a year in power.
Now it’s likely that a 700-watt power supply will cost more than $13 extra when compared to a 350-watt one, but considering how power supplies can last for years you may save money in the long run by buying a bigger one than you need.
350 Watt 80 Plus Gold Power Supply
- Low profile for mini PCs
- High efficiency with 80 Plus Gold certification
- Suitable for entry-level spec
700W Gaming Power Supply 80 Plus Gold
- Provides ultra-high power efficiency of 90% at typical load
- Ultra-quiet 120mm hydraulic bearing fan for minimal noise
- 5-year warranty
High-end PC
For the high-end PC we’re just going to assume a power supply that’s running at around 80-90% load by choosing a 700-watt power supply.
| PC power draw | Power supply | Estimated efficiency | Total average power draw | Average electricity cost per kWh | Cost to run per hour | Cost to run per day (8 hours) | Cost to run per year |
|---|---|---|---|---|---|---|---|
| 600 watts | 700-watt 80 Plus Bronze | 82% | 732 watts | $0.14 | $0.102 | $0.82 | $299.30 |
| 600 watts | 700-watt 80 Plus Gold | 87% | 690 watts | $0.14 | $0.096 | $0.77 | $280.32 |
The example here is even more stark – two power supplies rated for the same capacity, one is 80 Plus Bronze and one is 80 Plus Gold, and choosing the Gold one saves you around $20 a year in electricity, while the PC is still performing exactly as it otherwise would.
So it’s definitely worth trying to get the most efficient power supply that you can.
80+ GOLD 700W Power Supply
- 80 Plus Gold certified with 90% efficiency
- Active power factor correction
- 5-year warranty
Does an efficient power supply have other benefits?
When a power supply is converting the AC current to DC, a by-product is heat. The more efficient a power supply is, the less excess heat it generates.
This has three benefits. Number one is that it means the power supply will last longer. Heat is what will cause the power supply to wear out over time, so if it generates less heat then it won’t wear out as quickly.
It also means that the power supply doesn’t need as powerful a fan in order to remove that heat, so a more efficient power supply is usually quieter too. There are other factors that influence this, including the quality and design of the fan, but from the same manufacturer, a more efficient PSU will normally be quieter than their less efficient ones.
And thirdly, heat also affects the performance of your PC overall. While your PSU is normally positioned closed to a vented area on your case, the heat it generates won’t all be expelled. The difference in temperature is likely minimal, but anything you can do to bring down the overall temperatures inside your PC will have marginal performance gains.
What other factors are important when buying a power supply?
Obviously, the first thing you should look at when buying a power supply is whether it has the capacity for your PC’s power needs, and then efficiency is the second consideration.
After that though, you’ll want to look at a few other factors:
Modularity
Power supplies are either non-modular, semi-modular, or fully modular and this refers to whether the cables are fixed into the PSU or can be plugged in separately.
For a non-modular PC, all the cables are hardwired in. Semi-modular ones have certain key cables hard-wired but the rest are optional, while fully modular have no hardwired cables.
Semi-modular and modular are better because you only plug in the cables you need. This helps to keep your PC case tidier, which also improves the airflow (and therefore the cooling).
With a non-modular PSU, you’re more likely to have to bundle up and hide cables inside the system which will block some fan-driven air from moving around.
750w Semi-modular Power Supply
- 80 Plus certified with high efficiency under typical loads
- Silent and durable 140mm fan
- Semi-modular – easy to cable manage
850w Fully Modular Power Supply
- 80 Plus Gold certified with high efficiency
- Silent anti-vibrating fan
- Fully modular for easiest cable management
Warranty
Warranty is of huge importance when it comes to PSU power supplies. While they are generally long-lasting, you’ll want to make sure you get one with at least a 5-year warranty so that it matches the likely lifespan of your PC. That way, if anything did go wrong, you’d be able to get a replacement quickly.
Full Modular Power Supply 10 Year Warranty
- 80 Plus Gold certified with high efficiency
- Ultra quiet 140mm hydraulic bearing fans
- 10-year warranty
Brand
While you shouldn’t always judge things on brand name alone, it’s good to buy a power supply from a trusted name that you know has followed certain manufacturing standards. It’ll make them safer, and mean they’re more likely to last longer too.
Look out for names such as Corsair, Cooler Master, Seasonic, MSI, be quiet!, XPG, EVGA and Thermaltake.
FAQs
A bronze PSU is fine for gaming on a lower-end PC but if you have a high-end gaming PC, you’ll be wasting a lot more electricity. By upgrading to a Gold PSU you could save around $20 a year in electricity, depending on how often you use your PC.
An 80 Plus Bronze power supply from a reliable manufacturer should last you at least 5 years, while a more efficient one may last longer. Evaluate how long you intend to use your PC – if you’ll be building a new one in 5 years anyway, you may need a PSU upgrade regardless.
The power supply can only affect FPS (frames per second) where it’s underpowered and not giving the PC enough watts to run properly. Efficiency doesn’t matter here. Make sure you have a stable, high enough power for all your PC’s components to work as they should.
The power supply shouldn’t affect the temperature of your CPU, unless it is old and is providing an unstable voltage. If your CPU temperature is spiking and you have an old PSU it may need an upgrade. Wattage has no bearing on the temperature and performance of your processor.