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PSU Efficiency [What, Why & How]

PSU efficiency refers to how effectively a PSU converts the AC power from the inlet into the DC power for your system needs.

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The efficiency of your power supply unit plays a crucial role in overall system performance. Understanding PSU efficiency, why it matters, and how we can measure can help you choose or upgrade this crucial hardware.

Key Takeaways

  • PSU efficiency is the percentage of its effectiveness in converting AC power into DC power for the rig components.
  • There are multiple ways and certifications to measure the PSU efficiency like 80 Plus and Cybenetics certifications.
  • An efficient PSU is crucial; higher efficiency means lower power consumption, temperature, and noise level.

What Is PSU Efficiency?

Average Efficiency (Image By Tech4Gamers)
Average Efficiency (Image By Tech4Gamers)

PSU efficiency refers to how effectively a PSU converts AC power from the inlet into DC power for your system needs[1]. It is important to note that no conversion process is perfect and loses some energy in heat[2]. A highly efficient power supply means less wasted energy, lower electricity bills, and reduced heat generation[3].

How To Measure PSU Efficiency?

The efficiency of a power supply is usually measured in percentage. For instance, a 90% efficient PSU converts 90% AC power into usable DC power and loses 10% heat[1].

There are many methods and certifications to measure efficiency. Some of these are as follows:

  • 80 Plus Certification: This widely recognized certification measures efficiency at different load levels. The 80 Plus has several tiers, including bronze, Silver, Gold, Platinum, and Titanium. To qualify for this program, the PSU must have an efficiency of 80%[4].
  • Cybenetics Certification: This is a newer certification program that provides efficiency ratings across a broader range of load levels. Cybenetics also includes noise levels in benchmarks to give a more comprehensive picture of PSU performance[5].
  • Direct Measurement: While certifications offer valuable guidance, this approach involves measuring efficiency under controlled conditions[6]. It allows for more precise efficiency in a particular power supply.

  How Much Does PSU Efficiency Matter?

Tech4Gamers PSU Load Tester
Tech4Gamers PSU Load Tester (Image By Tech4Gamers)

The impact of efficiency depends on the factors given below:

  • Power Consumption: Insufficient PSUs may cause thermal throttling to the power-hungry system, resulting in more power consumption and heat output[7].
  • Electricity Cost: A more efficient PSU can also reduce electricity bills, as is evident in workstations or servers operating 24/7.
  • Voltage Instability: Under heavy loads, inefficient PSUs cause fluctuations in voltage stability that can damage the components.

Finally, while highly efficient PSU might come at higher prices, the long-term benefits outweigh the premium.

Helpful Resources By Tech4Gamers:


  1. What is power supply efficiency? – Sunpower UK. (2015, March 24). Sunpower Electronics UK.
  2. Clark, M. A., Choi, J., & Douglas, M. (2018, March 5). 15.3 – The Laws of Thermodynamics. Pressbooks.
  3. Evans, E. (2023, July 25). A Deep Dive into Bronze vs Gold Power. UKENERGYWATCH.
  4. 80 PLUS Power Supply Certification Program | CLEAResult.
  5. Cybenetics Labs – PSU Efficiency & Noise Level Certifications – Power Supplies. (n.d.).
  6. Efficient Power Supplies. (n.d.). Efficient Power Supplies.
  7. Replacing Your Aging Power Supply to Improve PC Performance – Computer Repairs. (2024, February 20). Computer Repairs.

Frequently Asked Questions

What is the good PSU efficiency?

A good PSU is generally considered 80% efficient or higher under loads.

What does 80% efficiency mean in PSU?

It means 80% of power input is converted into DC power, and the remaining 20% is lost in heat.

What is efficiency in a power supply?

PSU efficiency is the percentage of the power from the wall converted into useful energy for the components.

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