When you want to know what power you need in your power supply you have several options: you can calculate “by eye” the consumption of your hardware components, or you can use one of the many online power calculators , free tools provided by various manufacturers through Internet. However, how reliable are these calculators?
Generally, by looking at the TDP of the hardware components , we can get an idea of what power supply power we need when mounting a new PC. For example, if the processor has a TDP of 90 watts and the graphics card of 250 watts, adding the rest of the components whose consumption is considerably lower, we can know that we will need a power supply of at least 500 watts to service the system. .
We can calculate this by using one of the many online power calculators, which will give us an estimated value and recommend a specific power supply power. However, is this recommendation close to reality? Let’s check it out.
Power calculators for the power supply
There are many power calculators that we can find for free on the Internet. Several manufacturers have their own, although the most widely used and renowned is OuterVision , a tool that has been online for many years and is still up-to-date today.
For example, we used this calculator to measure the estimated power we will need for our test rig, consisting of an Intel Core i7-8700K, four Corsair Dominator Platinum RGB DDR4 3600MHz memory modules, an RTX 2080, an MSI Z370 motherboard. Gaming M5, an M.2 PCIe NVMe SSD, another SATA 3 SSD, multiple fans, and even multiple LED lighting strips.
This tool is suggesting us a 523 watt minimum power supply since it has calculated a maximum consumption of 473 watts, and recommends a 550 watt Corsair supply for this. We can select the efficiency of the source, and look for example how the cost changes and the source that they recommend us without instead of selecting an 80 Plus Bronze, we mark an 80 Plus Platinum.
This tool even recommends a certain power for a UPS, calculates the annual cost and tells us how many years according to the marked use (we have marked 8 hours a day) it will take to make the price increase profitable by selecting a Platinum source instead of Bronze. Of course, the data it provides is accurate and very valuable, and can help us choose a suitable power supply for the system. But is this data reliable?
Actual consumption tests
There is no better way to measure the actual consumption of a PC than with a wall meter. These devices are connected directly to the wall socket, and their thing is that we connect the PC to them, so that it can measure exactly what power it is consuming (most of these devices will give us more parameters, such as the current intensity in amps).
In the case of the example, the gaming PC that we have used in the online calculator has an average consumption in idle (simply being turned on at the desk) of about 110 watts. If we start a demanding game, such as Black Desert Online Remastered, consumption rises to about 360 watts more or less, and if we put the equipment at maximum load (with Prime95 to stress the processor and Furmark for the GPU), consumption goes up to 480 watts .
Therefore, the estimation of the online calculator is really quite correct, but although it would be worth us with a 550 watt source, we would not really recommend one of less than 600 or even 650 watts to have more margin, since as you know over time the sources degrade and deliver less power over the years.
In any case, the answer to the question is yes, the online power supply calculators are quite reliable and the estimate they make is quite valid when determining what power supply power we need for the equipment.