The power supply unit (PSU) is the component most people undervalue — until it fails and takes something else with it. A good PSU protects your entire investment. Here's how to pick one correctly.
How Much Wattage Do You Need?
Add up the TDP (thermal design power) of your major components: CPU + GPU are the biggest consumers. A system with a mid-range CPU (65W) and RTX 4070 (200W) needs roughly 300W at load. Add 20–30% headroom for efficiency losses and future upgrades. A 550–650W PSU is appropriate for that build. High-end systems with RTX 4090 or RTX 5090 may need 850W–1000W.
80 Plus Ratings Explained
80 Plus is an efficiency certification. At 20%, 50%, and 100% load, the PSU converts at least 80% (Bronze), 85% (Silver), 87% (Gold), 90% (Platinum), or 92% (Titanium) of AC input to DC power. In Nigeria where power costs money and generators are common, a Gold or Platinum PSU pays for itself over time compared to a no-name unit running at 70% efficiency.
Modular vs Non-Modular
A modular PSU lets you disconnect unused cables, reducing clutter and improving airflow. Fully modular is best for clean builds. Semi-modular keeps essential cables hardwired. Non-modular is cheapest but leaves you with a bundle of cables you can't remove. In a hot Nigerian climate, airflow matters — invest in modular if budget allows.
Brand Reliability
Established brands with strong reliability records include: Seasonic (best-in-class), Corsair (RM/HX series), EVGA (SuperNOVA series), be quiet!, and Fractal Design. Avoid no-name units from unfamiliar brands at suspiciously low prices — PSU failures can damage connected components.