Whether you’re trying to figure out your home energy budget or simply trying to cut back on your energy footprint, knowing how much power your PC consumes is a crucial part of the equation. And unfortunately, this isn’t as simple as looking at the label on your PC’s rear panel.
But that doesn’t mean it’s difficult. Instead of thinking of your PC as one indivisible unit, all you need to do is look at each individual component’s energy pull. Once you know that, you’ll have a much better sense of your PC’s power usage. Here are some things to keep in mind.
Energy Usage for Desktops
While your computer is likely comprised of many different components, there are five main components that draw most of the power. You probably don’t need to look further than these parts because the power draw of everything else is insignificant by comparison.
- Data drives
- Power supply
The good news? Finding the wattage for your PC’s components can be as easy as searching Google for each component’s model name. In particular, you’ll want to look for “technical specifications,” which should include wattage details.
CPU wattages can vary wildly. For example, take the low-end AMD Sempron 2650 APU (which is dual-core and only needs 25 W) versus the Intel Core i7-6900K (which is eight-core, insanely expensive, and needs 140 W). But for average, think of the AMD Ryzen 5 1600 (which is six-core and needs 65 W).
GPU wattages can also vary wildly. When you’re typing up an essay, it might not draw much power, but when you’re playing Crysis 3 with all graphical settings at Very High, it could be the most power-hungry component in your system. Most GPUs are rated by max pull. An integrated GPU, like the Radeon HD 8470D, may only need up to 65 W whereas the monstrous GeForce GTX 1080 Ti draws up to 250 W under heavy load.
RAM wattages are very low. An acceptable guideline to use is about 4 W per module. DRAM has far less static power consumption than SRAM, but energy usage can spike up to 10 W during heavy reading and writing.
Data drive wattages depend on HDD vs. SSD. For example, the Seagate 1TB BarraCuda HDD operates at between 5.3 W (500 GB and 1 TB models) and 8 W (2 TB and 3 TB models) whereas the similarly-priced PNY CS1311 SSD pulls 2.2 W when active and only 0.17 W when idle.
Power supplies can be tricky. At the very least, a power supply needs to be able to provide enough wattage for your entire system. But here’s something you may not know: the power supply pulls more power from the outlet than it provides to your system. This is because it pulls AC power (from the wall) and converts to DC power (for your PC components) and loses some energy in the exchange.
Using a power supply with 50 percent efficiency, you could be drawing 800 W from the wall to power your 400 W system. This is why a high-efficiency power supply is so crucial, and one of the main things to consider when buying your next power supply.
Energy Usage for Laptops
It’s much easier to estimate the power draw of a laptop versus a desktop for one simple reason: laptop energy usage is limited to the max wattage of the power adapter (AKA battery charger). If it wasn’t, you could experience battery drain while plugged in, and that wouldn’t be a happy time for anyone.
Let’s compare the energy usage of three laptop tiers.
- The 11.6-inch Samsung Chromebook 3 has a 40 W adapter, which fits in line with its casual user design and long-lasting battery life.
- The 15.6-inch Lenovo ThinkPad P50 has a 170 W adapter, which is enough for its purpose as a business workstation.
- The 17.3-inch Razer Blade Pro V2 has a 250 W adapter, which makes sense with its Intel Core i7-7820HK and GeForce GTX 1080. This thing was built to be an ultimate gaming laptop and it needs power for that.
As you can see, laptops use significantly less energy than desktops. Laptop CPUs and GPUs are specially designed to minimize energy usage (particularly when the system is idling) and these two components make up the lion’s share of system energy usage.
Also note that your laptop will only use the adapter-rated wattage under heavy loads. Most of the time, it’ll be much less. How much less? The only way to find out is to measure the energy usage yourself, but on average, idle power usage could range from 20 W (for a Chromebook) to 50 W (for a gaming laptop).
Energy Usage for Monitors
Monitors have pretty much become a status symbol among power users. The more monitors you have in your workstation, the cooler your workstation is. This trend becomes even easier to justify when you realize that multiple monitors really do boost productivity.
But if energy usage is a chief concern, you may want to reconsider. Even though modern LCD monitors are more efficient than old-school CRTs, their energy needs are still far from negligible.
Size has a non-negligible impact. Since monitor sizes are measured along the diagonal, every additional inch actually represents an exponential increase in total screen size. For a 16:9 aspect ratio, a 21-inch monitor has a screen area of 187 inches while a 27-inch monitor has a screen area of 311 inches — a 66 percent increase, but that doesn’t mean 66 percent more energy.
For example, compare the 23-inch ASUS MX239H with the 27-inch ASUS MX279H. The “typical power consumption” of each is 22 W and 29 W, respectively, which is only a 31 percent increase. Significant? Sure. Enough to sway you towards the smaller screen? Not really.
Screen type matters. People have long recommended LED monitors over traditional LCD monitors for energy-conscious folks, and that generally holds true even today. Compare the ASUS PB278Q LED to the ASUS MG279Q LCD, where the difference is 25 W and 39 W, respectively.
So if you want to reduce energy as much as possible, go for the smallest LED monitor that won’t impede your productivity.
The energy savings between a 15 W and 40 W monitor may not seem like a big deal, but it adds up fast when you have a multi-monitor setup. For a simple three-monitor workstation, that’s the difference between 45 W and 120 W. For a six-monitor superstation, that’s 90 W versus 240 W. And monitors are on all the time, so you’ll definitely feel it on your electric bill.
How can you mitigate some of your monitor’s energy waste? Screensavers won’t help you save energy. Instead, go into your operating system’s settings and set the display to automatically turn off after 10 minutes of no activity. Or even better, let your entire system go to sleep. There are many ways to set this up in a way that’s convenient for you.
Adding It Up: Your PC’s Power Needs
It’s impossible to give an “average wattage” for modern PCs. A weak build that’s only used to browse the web may never cross 100 W while a top-of-the-line build that runs heavy games may need 1,000 W for hours at a time.
There are three things we can say with certainty:
- Laptops use less energy than desktops.
- Idle wattage is more than you think, so turn off your PC when not in use.
- If you never do anything intensive (e.g. games, video editing), then you can save a lot more energy elsewhere. Heating and cooling are huge energy sinks, for example.
Did this answer your questions and concerns? If not, feel free to chime in below. If you have anything else to add, we’d love to hear from you too.