Whether you want to assemble your PC yourself or just want to give the old one a little more power: sooner or later you will need a new PC power supply unit. But which one is actually suitable for you? Does it really need 1200 watts to gamble? And what data can be used to determine this value? We address these and many other questions here. So read our little guide carefully and choose a power source that really fits your computer!
How does a PC power supply actually work?
In order to know which power supply you actually need for your PC, it is crucial to understand its function in the overall system . Basically, this component is one of the most essential. Because it supplies all other components – such as the mainboard, the graphics card and the CPU – with enough power so that they work at all.
But to do this, the PC power supply must first make the power from the conventional socket processable for the computer. Because originally this is direct current . But your components need alternating current. Accordingly, the power supply unit is actually a transformer. The same principle is also used for laptop power supplies.
But let’s get back to the computer itself. Because in order to supply the graphics card and Co. with power , you still need the appropriate cables. You may have noticed that the connections are designed completely differently depending on the component. That’s a good thing, because each of them requires a different amount of electricity. Accordingly, only the necessary power flows through the associated cables of the power supply unit.
But: which PC power supply do I need now?
Which is the best PC power supply for you depends on a wide variety of factors . Because depending on what you use your PC for and which components are installed, you will have different demands on your power supply. In order to make a decision here, we have put together a small guide to the most important properties for you.
The performance: How many watts does my PC need?
The most important point when choosing your PC power supply should without question be the performance behind it. Now of course you can just buy the most powerful model you can find. You’re basically not doing anything wrong with this because it will provide enough power to all of your components. However, it is an investment that in most cases, even for a high-end gaming machine, is simply not necessary.
A question of the overall system
Instead, you can make a calculated investment in your new power supply. The performance requirements depend on various aspects. We have roughly summarized these here:
- Processor : Newer CPUs are usually more energy-efficient, but especially for a gaming computer you need one with the appropriate performance – the more power it has, the more power it needs.
- Graphics card : Similar to the CPU, it is the case here that higher quality GPUs simply need more power. A high level of performance is required, especially for 3D representations.
- RAM bar : The number of bars has a small influence on the required wattage.
- Hard drives : In general, SSDs require less power than HDDs, but the amount still makes a difference here.
- Fan : The more fans are operated, the more power you need.
- Overclocking : If you intend to overclock your PC in the future, you should allow for a buffer when choosing your power supply.
On each of these components it should be noted individually how much power it requires. The best thing to do is to roughly add up these numbers. It is also important for you to know that a PC power supply works best with a load of 45 to 75% . The calculated value should therefore be in this range. It is best if you also allow for some additional buffer – so you can be sure that newer, possibly upgraded parts will also be adequately supplied with it.
But why not count on 100%? The reason lies in the conversion process. Because here – depending on the material used – around 80% of the electricity is usually lost . When buying your power supply, make sure that it has an 80-plus certificate. Because this guarantees you that at least 80% of the actual performance actually reaches your components.
What does it mean exactly?
Do you no longer have the packaging or is it just too time-consuming and fragmented to add up? Then best make your power supply selection based on how you use your PC . Because, as you can probably already imagine, an office computer needs significantly less power than a hardcore gaming computer. Here are some guidelines:
- Office computer : is mostly only used for documents, e-mail traffic and as a multimedia player – usually does not require more than 300 W
- Mid-range gaming PC : relies on components in the stable mid-range (e.g. NVIDIA GTX 1060, Intel i5 processor) – gets by with 400 to 500 W.
- A high-end gaming computer with powerful components (such as Intel i7 to i9, NVIDIA RTX 2080) needs around 600 to 750 W.
- Overclocked gaming computer : with components that run overclocked (often indicated by an OC in their name) – uses up to 1000 W.
So you see: To be on the safe side with your gaming PC and benefit from your power supply for a long time, a power supply with 500 to 700 W is usually sufficient. If you are not planning huge upgrades, but rather always look at current, but roughly equivalent parts, your power supply should also be a loyal companion to you.
By the way: Are you wondering what happens if the PC power supply is too weak? In this case, your components simply cannot be supplied with enough power. This in turn means that the computer will simply shut down, maybe restart again and again or not start up at all. However, it can also happen that your graphics card simply slows down – i.e. not performing at its maximum . If you experience these errors, it may well be that it is time for a new power supply.
For maximum performance: the power supply fan
In order to fully utilize the power of your power supply, you also have to make sure that it does not overheat . For this purpose, high-performance cooling systems are built into good products. A basic distinction is made here between the active, semi-passive and passive variants. A heat conducting material is used with the active, which leads the waste heat to a fan.
The sleeve bearing is particularly inexpensive – and quiet . Oils should dissipate the excess heat. However, it only works if the operating temperature remains consistently low. Such an option is not recommended for high-performance and gaming PCs.
In the case of a completely passive design, on the other hand, the PC power supply unit is prevented by the materials used from producing too much heat in the first place. The whole thing is useful when it comes to background noise, but it quickly becomes very costly. If you are looking for a solution in the mid-price segment and value a quiet environment, you should take a look at our blog post about water cooling .
Modular vs. non-modular: connections & cable management
As we look at it in another post, the case modding is no longer a rarity among gamers. More and more computers are pimped up with cool LEDs behind a plexiglass pane. But for the end product to be right, one keyword is particularly crucial: cable management! And as you know by now, a large part of this comes from the power supply.
So wouldn’t it be great if you could just take off the cables that you don’t need right now? This works out! With a modular power supply . Here you can easily unplug and plug in cables. This makes tidying up the computer a lot easier, because you can always fit the appropriate lengths and only use the cables that you need. This not only makes the inside of your computer look nicer, it also favors the flow of air. After all, nothing hangs in the way unnecessarily.
Nonetheless, non-modular PC power supplies also have their right to exist. Above all, they are still significantly cheaper . In addition, you hardly need any previous knowledge to use it and you don’t have to do a lot of research to find out which cables you actually need to connect. In computers, the insides of which cannot be seen anyway, the cables do not interfere with any further. So the decision is always a matter of personal feeling.
Conclusion: Your PC power supply has to be able to do that
If you now want to specifically decide on a power supply unit, we would like to summarize the most important facts for you here . It is crucial that your power supply is matched to the components. The more your computer is supposed to do, the more watts it needs. In order to get the maximum out of your power supply, a sophisticated ventilation system is essential. Because if this component overheats, it often means that your PC crashes. In the middle of an online game, that’s probably not what you want.
Finally, you should think about whether you want to invest a few more euros in a modular PC power supply. If you only work with standard components and only use one graphics card, this is not absolutely necessary. For a clean cable management or an absolute high-end computer, on the other hand, this investment often makes perfect sense. No matter how you decide, we wish you a lot of fun while playing!