We must break down into individual components to properly answer how long computer power supplies last. This will enable me to give you a complete answer to the question.
Although most people tend to use power supplies to the very end and only replace them once they stop working, I’d like to encourage everyone to take action earlier to increase the chances of your computer working reliably for longer.
A computer power supply should be changed after five years. After this time, it will most likely become less efficient and possibly cause a system to become unstable. The primary causes are aged capacitors and other components, power surges, heat, and other mechanical stresses.
With that very general rule of thumb out of the way, premium brands like Seasonic make PSUs that can last ten years or more.
So, How Long Do Computer Power Supplies Last?
Now that we have a general guideline about lifespan, let’s break things down further to paint a complete picture by looking at individual components that make up a power supply.
Note: The age of components discussed in this article is dealt with in actual running time, not shelf life.
What is a power supply?
A power supply is one of the main components of a computer that takes power from the wall socket and converts it from AC to a usable DC voltage, which usually consists of a +12 Volt, +5 Volt, 3.3 Volt, and in older supplies, a -12 Volt and -5 Volt outputs.
The motherboard, other internal components, and computer case use each specific voltage for various subcomponents.
A laptop doesn’t have a fully dedicated power supply like a desktop machine, but it does need one to supply a DC voltage to charge the internal battery.
The lifespan of individual internal components of a power supply
Like any electronic device, power supplies comprise a circuit board with components assembled and soldered onto it.
More unique to a power supply, you also find a cooling fan to keep components cool within the metal case.
This is probably one of the most common components that cause electronic faults, just like semiconductors. As these components age, the capacitance value alters, thus changing the efficiency at which your power supply works, compared with its original design.
The most commonly used power supply capacitor is an aluminum electrolytic capacitor. These capacitors are made of pure aluminum foil with aluminum oxide as a dielectric.
The expected lifespan of an electrolytic capacitor is a complicated question to answer. However, once the electrolytes evaporate past a certain point, the capacitor can no longer deliver the intended capacitance value.
Computer power supplies work hard, especially for gamers or other industry work that causes the computer to work hard for extended periods.
This means that the temperature that capacitors operate at, is going to be more likely higher compared to ordinary applications.
So, I would tend to lean toward the notion that the lifespan would be shorter than the average 10 to 20-year period.
When the capacitor’s values start deviating, other components like semiconductors and resistors can be at risk of running hotter depending on the circuit’s design. Thus lowering their life expectancy of them.
The common carbon resistor is another component that can alter in value as it ages. With the heat exchange from electrical to thermal (as by its very nature), resistors can slowly increase in value.
This increase typically does not hurt a capacitor. However, it can still offer irregularities that can cause computer components with a starved supply to point out just one example.
This degrading effect can be accelerated when a resistor’s power rating is too low for the task. This sometimes happens when circuits are designed, and a value isn’t chosen properly, thus setting the component up for a shorter lifespan.
Coils, inductors, and transformers
Generally, these are some of the most reliable components inside a power supply. While it’s true, I have encountered plenty of faulty transformers in my time, and it is generally due to a poor design that leads to failure.
Coils, inductors, and transformers are enamel-coated copper wires wrapped around plastic, ferrite, or magnetic core. Some inductors wound with thicker gauge wire can be manufactured and soldered into the PCB without a core.
These are not the most likely components that will cause a computer’s power supply to fail unless something physically damages them.
Integrated circuits have varying lifespans. This is due to a vast number of reasons. It depends on how hot the component gets over time and how long you can expect it to last.
Sometimes, due to poor manufacturing standards, a component like this can last for a short-term period.
Reputable manufacturers for ICs do help the overall cause, but it won’t be the only thing indicating its lifespan.
Factors like the circuit’s design as to how good the smoothing of a supply line is, how constant a voltage supply line remains under various conditions, or how much load the IC has to deal with all contribute to the lifespan of an integrated circuit.
Under the right conditions, ICs can last for a very long time.
Other semiconductors like MOSFETs, transistors, diodes, and voltage regulators are crucial in a computer’s power supply’s lifespan.
Voltages must be stable throughout the power supply, helping components receive the properly intended voltages required.
Regulators are components that take supply voltages and output a fixed voltage specified by the component’s value.
Semiconductors like MOSFETs and transistors do much of the work regarding power regulation with larger currents.
Over time, with many heating and cooling cycles, these components start losing efficiency and can produce current leakages.
Once a cooling fan stops working in a power supply, its lifespan will be considerably shorter.
Sometimes, when fans get old, the bearing inside can seize up—causing the fan not to spin at all or very slowly.
Of course, this is the worst-case scenario, and quite often, fans become noisy and draw more power as they age.
But if the fan slows down enough, cooling can be compromised for the power supply.
The average lifespan of a cooling fan is around 30,000 hours or three and a half years.
As you can see, many variables come into play when determining how long computer power supplies can last.
Given that some components are unpredictable, a specific age is very difficult to try and pinpoint.
At five years, some components like capacitors will start to degrade, and they won’t be doing their job as well as originally intended.
Efficiency will be affected, and while the power supply may run just fine, the average user won’t be aware of the smaller impacts affecting the system.
More serious symptoms of an old PSU may include freezing, spontaneous restarts, or shutdowns.
Given the negligible price of a computer power supply in most computers, replacing it with a new one seems prudent.