How Many Watts for a Power Supply Is Enough? | Small Business
By Steve McDonnell
A computer’s power supply unit is a critical component to the system that you should choose carefully. Add up the amount of power that each component in your computer will draw to arrive at the minimum wattage you need — and then add some more to plan for expansion in the future. The wattage of a power supply indicates how much power it’s capable of supplying, but it will only draw as much power as you need. For example, a computer that needs 300 watts of power will consume the same amount of power with a 500-watt power supply as a 1000-watt power supply.
Estimate Wattage
-
Most PSUs specify the maximum number of watts they output, usually between 200 watts and 1800 watts. To figure out how many watts you need to power your computer, you should itemize the components with their individual power demands and sum them to arrive at a total. You can use the estimates provided in the next section or an online calculator such as the PSU Wattage Calculator from Thermaltake that provides a detailed questionnaire, including how you plan to overclock your computer, to help you arrive at a the total wattage required.
Typical Power Requirements
-
As a general rule of thumb, an AGP video card uses between 30 and 50 watts of power. A PCI Express video card uses 50 to 150 watts, or it might use 150 to 300 watts if it has an additional power connector on the card. Regular PCI cards consume between five and 10 watts. A CD or DVD drive will take about 20 to 30 watts and a hard drive consumes between 15 and 30 watts. Your motherboard probably uses 50 to 150 watts, and each stick of memory requires about 15 watts. The processor needs between 80 and 140 watts of power.
Planning for Expansion
-
Purchasing a power supply that provides exactly or close to the power you need today is probably not enough. You should purchase a power supply that provides more power than you need in case you decide to expand the computer. For example, if you decide to upgrade your video card and the card requires additional power, you don’t want to have to replace the PSU in addition to the graphics card because you didn’t plan for expansion.
PSU Efficiency
-
The actual amount of power that you use will vary based on how you use the computer. Processors and video cards don’t always operate at their maximum capacity, and the amount of power they draw will vary based on their utilization. Power supplies also lose some of the power they supply as heat, a measure called efficiency. An 80 percent efficiency, meaning that 80 percent of the rated wattage is provided as power and 20 percent is lost as heat, is considered good. Some power supplies will have an 80-Plus certification logo, indicating they are at least 80 percent efficient.
References
- PC World: How to Pick the Best PC Power Supply
Resources
- Thermaltake: PSU Wattage Calculator
Writer Bio
Steve McDonnell’s experience running businesses and launching companies complements his technical expertise in information, technology and human resources. He earned a degree in computer science from Dartmouth College, served on the WorldatWork editorial board, blogged for the Spotfire Business Intelligence blog and has published books and book chapters for International Human Resource Information Management and Westlaw.
How Much Power Does a Motherboard Use? |
Building a PC for the first time can be super intimidating. Pick the motherboard that matches the CPU. Pick the right RAM for the board. Choose how awesome the LEDs should look. Figure out how much all that will need power-wise!
When it comes to optimizing your PC build, you should know the answer to how much power does a motherboard use. Luckily, we’re here to help!
How Much Power Does a Motherboard Use?
On average, the motherboard itself will use 30 to 80 watts per hour. This range depends on the type of motherboard you are using (gaming motherboards tend to draw more power) as well as the current status of the motherboard. If overclocking components, expect the motherboard to draw in more power than if your machine is currently idle.
How to Check How Much Power your Motherboard is Using
If you’re looking to optimize for both performance and energy efficiency, it’s a good idea to know exactly how much power your whole build will need, motherboard included.
When the machine is active, however, it’s a lot harder to know exactly what your motherboard is doing power-wise.
There are two methods to try and validate its power usage:
- Refer to the manufacturer’s website and perform some manual calculations.
- Use a software solution that watches power consumption live.
Yep, that is all there is to it. Let’s discuss a bit about the software solution. Depending on the manufacturer of your PSU, motherboard, or other components – they may offer 1st party software that relays some information related to power usage back to you. For example, Corsair has a series of Corsair Link-enabled PSUs that allow you to see the temperature, fan speed, and voltage of the PSU.
Other freeware and open source software such as HWMonitor and Open Hardware Monitor attempt to provide 3rd party solutions that can read all the components’ power usage at once. However, depending on the chipset you are using, these tend to not be a one size fits all option.
So, if the software is hit or miss, the alternative is to do some research on the manufacturer’s website and use a physical energy monitor. Physical energy monitors typically plug into a wall socket and provide a passthrough for the power cable from your PC to the electrical outlet.
To utilize this method, we recommend finding the expected power usage of your CPU, sticks of RAM, and GPU while idle. Again, this will probably have to be guessed based on manufacturer specifications. Once you have that information, disconnect any USB devices, Bluetooth devices, and the internet from your machine. This step is to remove any additional power being drawn by these items from the motherboard.
Use the physical monitor to track usage over 1 hour then take down the results. Subtract all the parts you are 100% certain of (don’t subtract the motherboard) and the final number you’re left with should be an estimate of the idle power usage for your motherboard. While this is super dirty to get to, we think it’s a far more reliable method than using one of the software solutions.
To go the other path, seeing how much the motherboard is drawing at its peak, you would follow a similar process:
- Use the manufacturer’s site to calculate power usage for CPU, GPU, Memory, etc. at max use
- Plug everything you can into USB ports, connect a Bluetooth device / connect to wireless networks
- Run a highly demanding graphical benchmark such as 3DMark.
- Subtract the usage for everything but the motherboard after the benchmark ends. You may have to do some calculations to get to what the expected draw is per hour (so if it ran for 5 minutes, multiply the result by 12 to get the motherboard’s wattage per hour).
So now that you have a general idea of how much power your motherboard uses when idle and when under stress, what exactly makes the motherboard’s power usage go up while in use?
- YOU MAY ALSO LIKE: Best Budget Motherboards Under $100
Things That Drive your Motherboard Mad
Clever subheading aside, how much power does a motherboard use depends entirely on the components installed and the functions the motherboard is carrying out.
As you may already know, the motherboard is essential to every PC’s function. Should it fail, you are pretty much rebuilding unless you’re very lucky. This essential tag comes from being the home of USB connections, the CPU, the GPU, any other PCIe slotted items, and even wireless connectivity options such as Bluetooth and Wi-Fi on select models.
The more the motherboard takes on, the more power it needs to continue to drive these functions. As such, the more USB devices are drawing power, the more simultaneous wireless connections (Bluetooth or otherwise) are made, and the more the GPU, CPU, RAM, or hard drives work, the more power the motherboard requires.
That said, if you’re looking to lower your motherboard’s power usage, you can limit overclocking the GPU or CPU, turn off your awesome LEDs sometimes, and of course unplug items from USB ports that are not being used currently. Again, since the draw is pretty small overall, the differences may not add up to much but could make the process of choosing a PSU a lot easier.
- RELATED ARTICLE: Best RGB Motherboards
How to Pick the Right PSU For your Motherboard
Over the years, we’ve built quite a few PCs and can honestly say we don’t typically worry too much about which power supply to grab in consideration of the motherboard.
Depending on whether your PC build is low or high-end, your power consumption will go from low to high respectively. This is due to higher-end gaming PCs running top-tier graphics cards and CPUs that require bigger power supplies. These will almost always cover the motherboard’s wattage.
To give an example, the recent RTX 3090 Ti is estimated to use between 450 to 550W when at max. The intel 12900K CPU uses around 150W when at full use. This means you are already looking for at least a 750W or higher to run both comfortably.
If you are really wanting to be exact though, add about 100W on top of the CPU and GPU usage to be super sure you’re covering the motherboard, ram, and any other components that will be installed.
This would push that 700W number up to 800W which would mean grabbing an 850W PSU would cover your system with a bit of wiggle room.
Another consideration for all PC parts (especially for motherboards) is finding a PSU with the best 80 Plus rating. Having a gold or better 80 PLUS rating (Platinum, Titanium) means your system gets more of the energy the PSU is rated for with less heat. This will make the fans spin less freeing up energy for other components.
- READ ALSO: Best Water-Cooled Motherboards
Final Thoughts
So in closing, knowing how much power does a motherboard use can save you a headache when it comes time for your next custom gaming PC build or otherwise. To ensure you cover the motherboard’s 30 to 80W expected usage, add 100W on top of your expected GPU and CPU power usage then get a power supply that covers all of the components comfortably.
Should you want to calculate how much your motherboard is using currently, we recommend doing a little bit of research to find the expected usage for all of your parts, using a physical energy monitor, then subtracting all components’ energy usage to find the motherboard’s true power usage.
Feeling all charged up after that one? If you have some other ways to calculate a motherboard’s power usage you’d like to share, leave a comment below. We love hearing from you!
- RELATED READING: Best White Motherboards
Electricity consumption of a desktop computer
With the constant increase in electricity prices, it will be good to know how much electricity is consumed by various devices. This information will help in the future to significantly save money on electricity bills. In the proposed article, we will consider how much electricity a personal computer consumes, how to correctly calculate its energy consumption, and what needs to be taken into account in such a calculation.
What to consider when calculating the electricity consumption PC
To understand how much electricity a home desktop computer consumes, you should not study the power supply in search of the required value. When calculating, it should be taken into account that electricity is consumed by all components of the computer and its peripheral devices.
In addition, the nature of the use of the PC also affects the consumption of electricity.
System unit consumption
You can find out how much power the system unit consumes from the technical documentation that came with your computer. Indeed, in fact, its maximum possible energy consumption is the power of the power supply, since it is from it that all the components that make up the system unit and some peripheral devices are powered. The power of the power supply varies from about 300 watts per hour on simple PCs to 1600 watts per hour or more on powerful gaming machines. But you should know that these are the values \u200b\u200bthat the power supply can produce, and not how much the computer actually consumes. In fact, to find out exactly how much light a personal computer consumes, it is necessary to sum up the power consumption of all its components. The most active consumers are the processor and video card. nine0003
Motherboard
The power consumption of the motherboard depends directly on the capabilities built into it by the manufacturer.
On average, it needs from 20 to 35 watts to power it, but if coolers, a graphics processor, a sound card and other elements are connected to it, its power consumption increases significantly.
Processor
Processor performance — this parameter determines how much power it will consume. Dual-core processors running at low frequencies will consume much less than eight-core ones. But at the same time, it should also be taken into account that the old options are always more energy-intensive. For example, a quad-core Intel Core i5 consumes up to 140 watts of electricity, while an Intel Quad Core consumes more than 200 watts per hour at maximum load. But dual-core AMD spend on average from 65 to 95 watts, while more powerful options from this manufacturer consume approximately 95 to 125 watts per hour.
Video card
In a video card, as in a processor, power consumption directly depends on the power. High-performance devices at heavy loads consume an average of 240 to 350 watts per hour, and in idle mode, their consumption varies from 35 to 55 watts.
But since the video card is not always used at full capacity, the power consumption for its operation can be considered on average from 100 to 300 watts. nine0003
Hard Drive or SSD
The power consumption of a conventional hard drive ranges from 0.7 to 6 watts on average, while more modern SSDs consume less — from 0.6 to 3 watts per hour.
Optical drive
Under load, the optical drive consumes an average of 27 watts of power, while in idle mode it consumes no more than 15 watts.
Fans
The computer cooling system draws between 0.6 and up to 6 watts of electricity, it should be noted that the fans are constantly running, and as a rule, any stationary computer includes several coolers. nine0003
Peripherals
The question of how much power is taken by the computer peripherals can be answered by the numbers indicated in their technical specifications or on the factory stickers attached to the back or bottom of them. It should be noted that the monitor works directly from the mains and consumes approximately 18 watts or more, depending on the model.
And the power consumption of other devices, such as a webcam, speakers, headphones, keyboard and mouse, comes from the interfaces of the system unit, and therefore their power consumption will not exceed the specified maximum power supply. By the way, the speakers can also be powered directly from the 220 V network.
Power consumption by usage
The power consumption of a computer depends not only on the power of its components, but also on the nature of its use. After all, it is obvious that a computer in sleep mode spends much less energy than when running resource-intensive games and applications.
Idle
A computer that is idle, that is, when no user activity is performed on it, consumes an average of about 78 watts of electricity. In this state, PC devices still draw electricity, but in small volumes. nine0003
Sleep or power save mode
Depending on the performance of the personal computer, it will consume approximately 20 to 40 W per hour in sleep mode, and up to 10 W per hour in power save mode.
For a month, this can average from 2 to 15 kilowatts, especially when you consider that the system unit, being in the off state, consumes current: the power supply is powered, the motherboard is powered (but only to the signaling line of its state), memory power. nine0003
At maximum performance
Power consumption is significantly affected by resource-intensive programs and games that run on the PC, as well as the time spent using them. On average, this value at maximum performance ranges from 170 to 200 W per hour.
How to calculate the amount of power consumed by a PC
There are several ways to calculate how much power a personal computer consumes. To do this, you can use various computer programs or take measurements using special measuring equipment. nine0003
Measuring Equipment and Utilities
Accurate measurements of power consumption can be obtained using a conventional wattmeter for this purpose, with which you can measure the power of the electric current flowing to the PC.
To do this, plug the device into a power outlet, and connect the power supply plug to it. After turning on the PC, the exact value of the power consumption of the computer will be displayed on the wattmeter screen.
Electricity consumption can also be measured using special online services on the Internet. The most famous of them are the eXtreme Power Supply Calculator, a handy and simple PC power calculator, and MSI’s power supply calculator. nine0003
Average consumption
The example shows how much electricity a typical desktop computer consumes. Let’s take the average case when a personal computer works for about 5 hours. As practice shows, the actual consumption of electricity by an average system unit, regardless of the values on the power supply (even 1000 watts), varies from 100 to 180 W * h during normal use (Internet surfing and other processes that do not use large computer resources) , and up to 350 Wh with a significant load on the machine (this is work in resource-intensive programs, powerful games).
Therefore, given that games can sometimes be played on an average PC, the average power consumption will be (100 Wh + 180 Wh + 350 Wh) / 3 = 210 Wh. The approximate cost of electricity by the monitor is up to 40 W * h. The result is: 210 W * h + 40 W * h \u003d 250 W * h. Multiplying the resulting value by 5 hours and adding the electricity costs of the computer in the off state, the remaining 19hours — approximately 4 W x 19 h \u003d 76 W, we find the required amount of electricity consumed by the PC per day — 5 h x 250 W * h + 76 W \u003d 1.326 kW, which is equal to 39.780 kW per month.
How to reduce energy consumption
To reduce your personal computer’s energy consumption, follow these tips:
- Choose energy efficient options.
- Set optimal power settings in PC settings. nine0076
- Turn off PC when not in use.
- Do not set the monitor to maximum brightness, and if possible turn it off when the computer is idle.
- Replace old components with new, more efficient ones.
- Use less powerful laptops unless you absolutely need a powerful desktop computer.
In order to save on electricity and not spend a significant part of the budget on working at a computer, it is best to choose either a ready-made modern computer or components for it that will be more energy efficient, which will save your money significantly. And to help you choose a model that absolutely meets all your requirements, qualified specialists of our online store will help. nine0003
Rate this article:
How to calculate the power supply for a computer?
10816 views
Computers
5 comments »
17 May 2017
We are talking about stationary computers, which consist of separate elements. Including in such a system unit there is a power supply, thanks to which all these elements work.
If the power of the power supply is not enough, then the performance of the computer will decrease or even turn off.
It can also lead to damage to the power supply itself. nine0003
Therefore, later in the article I will tell you how to correctly calculate the maximum power supply required .
- Find out the model of the motherboard. We are looking for its characteristics on the official website and look at the power consumption. If such information could not be found, then we are trying to determine the class of the motherboard: Low ed — about 50 watts, middle class — up to 75 watts or Hi-ed about 100 watts.
- RAM power consumption. It’s simple: DDR2 and DDR3 up to 1600 MHz — 1 watt, DDR3 from 1866 to 2133 MHz — 2 watts, DDR3 2400 MHz — 3 watts, DDR3 above 2400 MHz — 4 watts, DDR4 — about 5 watts. nine0076
- Hard disk power consumption. Modern HDDs consume on average about 25 watts. There is also a GREEN class HDD, their consumption is about 10 watts. An SSD drive consumes an average of 2 watts.
- Disc drive power consumption.
And although this device is no longer being installed in system units, it is still not uncommon. DVD drive consumes up to 30 watts, Blue-Ray also up to 30 watts. - Fans. Modern case fans consume on average about 10 watts, processor fans up to 30 watts. Each fan has a sticker that indicates the maximum consumption. nine0076
- Separate sound card up to 30 watts, separate network card up to 20 watts, TV tuner up to 50 watts, video capture card up to 80 watts. There may be other secondary devices as well.
- The consumption of devices connected via USB is a maximum of 7 watts each.
- Processor power consumption. To find out this indicator, you should find the specifications of your processor on the official website of Intel and AMD. On average, about 150 watts, but can be either 50 or 300 watts.
- With the power consumption of video cards the same story. NVIDIA and AMD. Modern video cards are trying to do with less power consumption, but with good performance.
