Page 1:Brought To You By Granny’s Radio
Page 2:How A Switching Power Supply Works
Page 3:Efficiency, Efficiency, Efficiency!
Page 4:Of Power Factors, Apparent Power And Effective Power
Page 5:How To Spot An Efficient PSU?
Page 6:Don't Get Burned: Safety Before Stinginess
Page 7:Reliability Above All: Caps And Fan
Page 8:How To Determine Your Power Requirements
Page 9:The Power Window Is Important
Page 10:Example 1: The Office PC
Page 11:Example 2: Mid-Range Gaming PC
Page 12:Example 3: The Enthusiast’s System
Page 13:If You Don't Like Our Advice, Buy A Fire Extinguisher
How To Determine Your Power Requirements
A Matter Of Simple Addition
While there are many online calculators meant to help you figure out how much power your build will use, they all estimate its maximum requirement. They then take into account the PSU’s peak efficiency at a load of 50 to 55 percent and make a (generous) projection based on those numbers. The drawback is that this method does not consider consumption when the computer is idle, which we already determined is where efficiency often appears worst.
The following table is meant as a guideline, showing you how much power a certain component is likely to use under a specific load. If you know the exact figures for your components, plug them in instead and do the math.
|Component Type||Description||Idle (W)||Load (W)||Number Installed|
|CPU||Current dual-core CPU|
Current dual-core CPU, overclocked
Current quad-core CPU (Mid-range)
Current quad-core CPU (High-end)
Current quad-core CPU, overclocked (High-end)
Older dual-core CPU (AMD)
Older dual-core CPU (Intel)
Older single-core CPU
|Motherboard||Current microATX board without graphics|
Current microATX board with graphics
Normal mid-range board without graphics
Normal mid-range board with graphics
High-end board, overclocked
|RAM||Current DDR2 or DDR3 RAM, per 2GB module|
Current DDR2 or DDR3 RAM, per 4GB module
Overclocked RAM per module (estimated)
|HDD||Conventional hard drive||2||8-10||Varies|
|SSD||Current solid-state drives||1||4||Varies|
|Fan||Normal CPU fan, mandatory|
Silent case fan
Performance case fan
|Add-In Card||External sound card|
|Graphics Cards||Current office-oriented card|
Current mid-range gaming card
Current high-end gaming card
|Other||Cold cathode lighting, modding parts, etc.||See manufacturer info||Varies|
Now that we have an idea of how much power each component draws, calculating the overall consumption at idle and under load is easier. Based on this information, we will define a power window in the next chapter and choose the best PSU for the job.
- Brought To You By Granny’s Radio
- How A Switching Power Supply Works
- Efficiency, Efficiency, Efficiency!
- Of Power Factors, Apparent Power And Effective Power
- How To Spot An Efficient PSU?
- Don't Get Burned: Safety Before Stinginess
- Reliability Above All: Caps And Fan
- How To Determine Your Power Requirements
- The Power Window Is Important
- Example 1: The Office PC
- Example 2: Mid-Range Gaming PC
- Example 3: The Enthusiast’s System
- If You Don't Like Our Advice, Buy A Fire Extinguisher