Computers and power consumption

Note: In this post, I will discuss only desktop computers because most of what I will say, will not apply to notebooks.

Sooner or later most of us will decide that it is time to buy a new computer. As I wrote before, if you can, it is always better to buy parts and assemble them yourself. You will get a much better, much faster PC and what is more important, you will get it much cheaper.

But what should you buy? There are multiple discussions about that, but today I would like to talk about power consumption. Imagine you decided to spoil yourself and decided to buy top of the top. Or simply the best! At the moment of writing it will be Ryzen 9 7950X and NVIDIA 4090. You know that they both consume a lot of power and you just need to be careful and select the power supply that provides enough juice and that’s it, right?

But unfortunately, the answer is no. Your problems are just started. And I will explain why. As you know, most energy consumed by electronic components will be converted to heat. So if components inside your computer consume 700 watts, it means that most of that energy will go to heat. Effectively, your computer will be a heater. Let me explain, what problems it will bring.


Because your computer will produce a lot of heat, you will need to effectively remove that heat from the computer. It means you have to buy a good case and very often it means an expensive case. And also you need to think very carefully about its ventilation. Otherwise, your computer will overheat then throttle, and as result work slower than it can. Also, excessive heat in your case can considerably reduce the lifespan of other components.


Because your computer works as a heater, it will heat the room you are in. And during summer, you will have a problem because your room will be very hot. If you don’t have an air conditioner, then you will literally sit in a sauna unless it is the North Pole.

If you have an air conditioner then it is more or less ok. But even in this case, your air conditioner has to spend a lot of energy to cool your room. If your components consume 700W of power, together with the power supply and monitor they likely will consume around 850 watts. The air conditioner will consume close to 2000W to cool that amount of heat as it is about 30-40% efficient. So together, your computer and air conditioner will consume close to 3000 watts of power.

Electricity cost

As many of you know, the current prices of electricity are going up. Especially in Europe. And as result, 3000W will cost quite some money.


There is only one way to cool modern computers – using fans. Fans blow cold air from outside of the case then that air heats up and hot air is blown outside of the case. The more power some part consumes - the more air it needs to cool and thus fans have to bring more air.

But air contains dust and the more air the more dust. Sure, many modern cases have dust filters, but they just reduce the amount of dust, and dust still goes inside. And as result, you will have to clean filters and the inside of your PC often. And the more air going through your computer, the more dust it will accumulate.

But some components are quite hard to clean. The fins of the heatsinks are one of the places that are really hard to clean and eventually dust will start accumulating there and not much you can do without taking the heatsink outside of the computer. And even then, some places are simply too dangerous to clean. And if you live in a humid environment, then this dust can kind of glue to components.


The more air comping inside the more noise you will hear. Moreover, with time, the effectiveness of thermal paste will deteriorate, and heatsinks will cover with dust that reduces their effectiveness. As result, fans have to spin even faster bringing even more dust and noise.

It is really hard to measure the noise effect on people, but most people agree that the more noise, the more people are tired at the end of the day.


Based on this, you should be careful when you select computer components. In some cases, you may get more trouble than joy out of your big spending. And probably better to pick up slightly slower components that consume much less power.

Of course, all of that is not applicable when you are using your computer to get money. If you are rendering stuff that takes weeks to finish, you need to get it as fast as possible, because it means saving hours or days.

But in any case, it is just a word of advice based on experience, and feel free to do what you want.

I hope it will help someone.