PC power supply buying guide: choosing the right wattage

A PC power supply is chosen first by its total wattage, which determines whether it can run all your components. The twelve-volt rail capacity then dictates compatibility with high-performance processors and graphics cards. Finally, the number of SATA connectors defines how many drives and SSDs you can install.

What to check

Check the total power output Total power, measured in watts, indicates the maximum energy the supply can deliver to all your components. Current market values range from 120 W for very basic setups to 1,600 W for heavily equipped machines, with a median of 750 W. The site score positions each model within this scale: the longer the bar, the more energy the supply can provide to demanding components. Insufficient power causes unexpected shutdowns, while unnecessary surplus increases cost and daily electricity consumption. Match the wattage to your actual needs, leaving some headroom for stability. Market median: 750 W

Verify the 12V rail power The twelve-volt rail specifically powers the processor and graphics card, the two most energy-hungry components. This combined power ranges from 456 W for entry-level models to 1,300 W for the most robust, with a median of 798 W. The displayed score compares each supply against these benchmarks: the longer the bar, the better it supports high-performance components. Too little capacity limits your choice of graphics card and processor, while a comfortable margin ensures stability even under maximum load and leaves room for future upgrades. Market median: 798 W

Count the SATA connectors SATA connectors power hard drives and SSDs. Their number ranges from 3 on compact supplies to 14 on the most versatile, with a median of 6 connectors. The site score reflects this capacity: the longer the bar, the more storage devices you can connect. Each drive or SSD requires a dedicated connector, so a setup with multiple storage units needs generous connectivity. Anticipating your needs prevents being stuck when adding a new drive later on. Market median: 6

Plan the installation A PC power supply fits inside the case, typically at the bottom or top depending on chassis design. Check that dimensions match the available space and that cable lengths reach all components, especially the motherboard and graphics card if positioned far away. Modular cabling, when offered, simplifies cable management by connecting only necessary wires. Ensure sufficient airflow access: a poorly ventilated supply overheats and ages faster. Proper positioning and ventilation extend lifespan and maintain stable operation.

Benchmarks based on 30 recent market listings, collected on 4 October 2026.

What you get for each budget

Under €50

Power supplies in this range typically offer modest wattage suited to office configurations without dedicated graphics cards, with limited SATA connectors and reduced twelve-volt rail capacity.

€50 to €100

This level provides wattage close to the market median, sufficient for most balanced builds with mid-range graphics cards, adequate SATA connectors, and comfortable twelve-volt rail capacity.

Over €100

Models in this range offer high wattage capable of powering demanding graphics cards and multiple drives, with generous combined twelve-volt rail power and extensive connectivity for upgradeable configurations.

Frequent mistakes

Choosing total wattage barely sufficient for the current setup, leaving no margin for a more powerful graphics card later.

Overlooking twelve-volt rail power while focusing only on total wattage, even though it powers processor and graphics card.

Underestimating the number of SATA connectors needed if you plan multiple drives or SSDs.

Forgetting to verify supply dimensions against available case space.

Ignoring cable length, which can cause issues in large cases or unusual configurations.