Zit Seng's Blog

A Singaporean's technology and lifestyle blog

PC/NAS Power Consumption

I built a PC-based NAS a couple of years ago. If you, like me, run a PC on a 24×7 basis, you might have a concern over its power consumption. How much power does the PC consume? Not much, surprisingly.

This may come as a surprise to many PC enthusiasts, especially if they are familiar with picking out Power Supply Units rated around 500 to 600 Watts. Shouldn’t a PC consume at least a few hundred Watts at least?

This question recently came up during a discussion with a friend. I shared about my measurements from a few years ago. It seems too good to be true. The NAS, at that time, wasn’t yet fully operational, though it was nevertheless a good indication of how much the PC would nominally consume.

That PC, which I built to operate as NAS, runs 24×7. It has had some hardware additions, and new software loads. It’s also been quite a few years. Perhaps it’ll be good to do a re-check of its power consumption?

In normal steady state, power consumption generally hovers around 55 to 58 Watts.

The lowest the power drops to is 51.1 Watts. The highest to climbs up to is 75.1 Watts.

To get a sensible average reading, I measured energy consumption over one hour. This PC consumed 0.054 kWh over one hour. In other words, the average power is 54 Watts.

Other interesting numbers: Standby power on this PC is 3 Watts (i.e. “off” but plugged in), and power up peak consumption hits 116.7 Watts.

Just in case you are wondering, this is not a bare bones PC. It is decently configured with an Intel Pentium G4560 processor with 32 GB of RAM. You can read about this PC’s build in my 2017 blog post. Since then, some hard disk drives have been replaced, and some additional ones installed. Right now, there are 5x Seagate IronWolf NAS drives. The NVMe stick is still there too.

I run FreeNAS on this PC, serving two Zpools (not including the boot). On top of that, I have three Virtual Machines running in there. I run my Nextcloud server (i.e. private Dropbox) in there, along with several other personal web apps and experimental projects. Although this PC isn’t very busy, it also isn’t something that just sits idle all day.

Using the awesome electricity rate I get on a Wholesale Electricity Plan, which in March saw me getting an average rate of 14.54 cents per kWh (inclusive of GST), the whole-year electricity cost of this NAS comes up to about $68.78 (inclusive of GST).

Sounds like a pretty good alternative to hosting a bunch of VMs in the cloud.

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