How to Measure Your Computer's Power Consumption?

Posted , by Denis Sokol (Last update )

With the cost of electricity rising everywhere, many people are thinking about reducing energy consumption and want to estimate how much energy household appliances consume. Have you ever asked yourself: “How much power my computer is using and how much I pay if it works 24/7?”.

How to check how many watts your Windows PC or Mac is drawing? Do you have a NAS at home and worried about its power consumption? In this article, you will find a study of how much power a QNAP NAS consumes. This post is part of a series on upgrading an old QNAP NAS to run FreeBSD on it, but the focus here is on energy consumption research.

Setup for energy usage measurements

See picture above. QNAP TS-469L and TS-469 Pro connected to iSocket with electricity meter. The gray cable goes to TS-469 Pro and the black one goes to TS-469L.

In the next video, I turn on my NAS remotely. First you see the historical (6 minutes ago) idle power consumption, then I refresh the data and you see the current power consumption of both NAS with all 4 hard drivers. Then I turn off the NAS and you don't see any energy consumption (no standby current because it was turned off completely - like you pull the plug out of the NAS).

Let's go through all the possible modes step by step. In the following pictures you can see standby power consumption and energy use of bare NAS hardware without hard drivers in the bay.

Let's first try with two hard drives for each NAS, but of a different type.

Two 2.5" laptop hard drives will fit TS-469L and two 3.5" laptop hard drives will fit TS-469 Pro.

As a result, iSocket shows the following power consumption:

If you compare the screenshot above showing the power consumption of the bare hardware, you can see that the laptop drives have almost no effect on power consumption. Let's now place all 4 hard drives, where for TS-469L we will put all 2.5" (including one SSD) and TS-469 Pro will be equipped with 3.5" hard drives.

Below you see the total power consumption as you saw in the video. The power consumption is slightly lower than what you saw in the video because the video shows a power scenario where the coolers spin faster and consume more power on the power on scenario.

And this is a live demo video where I show you how the test was performed. It first shows iSocket devices with a NAS attached to it. The outlet on the iSocket itself is energized, but the NAS is in standby mode (turned off by the button on them). First, I show you the standby energy consumption. I then turn on the NAS using the buttons and display their energy usage without hard drivers. After installing two hard drives in each bay, we check the power consumption again. Then we check the power consumption with all disks. Finally, I shut down each NAS remotely using iSocket - you can see and hear that. The red OUT LED indicates the status of the socket on the iSocket - you can see the LED turn off when your device is not receiving power (the outlet on iSocket is not energized).

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