How it works
A computer power supply converts mains electricity into the voltages its components need. Its rated output, connectors and physical format must suit the complete system. An efficiency rating describes the relationship between power drawn and useful output; it is not an extra output allowance or proof that every installation is suitable. Cooling, operating conditions and the manufacturer's specifications also matter when selecting a supply.
Modular cables are not universally interchangeable. A connector that fits a socket can have a different electrical pin assignment, even within one brand's product range. Reusing an old cable with a replacement supply can damage connected components. A system that switches off under load may have a power problem, but temperature, connections and other faults can cause similar symptoms. The symptom alone does not establish that a larger supply will solve it.
Practical checks
Record the exact supply and component models, then check documented output requirements, cable compatibility and case dimensions. Use only the cables approved for that supply and connect them according to the manual. Disconnect mains power before installation and follow the equipment's safety procedure. Never open the power supply enclosure: internal components can retain dangerous energy after disconnection. After a compatible replacement, test the original workload and verify stable operation rather than assuming a new part proves the diagnosis.