Wattage: how much do you need?
**Safe rule**: System TDP + 30% headroom. RTX 3060 + i5-12400 = 200W TDP → 650W PSU. RTX 4080 + i9-14900K = 450W TDP → 850W PSU. RTX 4090 + i9-14900KS = 550W TDP → 1000W PSU. Better to oversized than undersized. Larger PSU runs cooler (longer lifespan).
80+ Bronze vs Gold vs Platinum efficiency
**80+ Bronze**: 85–88% efficiency, cheaper ($60–80), acceptable heat. **80+ Gold**: 90%+ efficiency, $80–120, less heat, longer lifespan. **80+ Platinum**: 92%+ efficiency, $150+, rarely needed for home use. Gold is the sweet spot for builds over $800. Bronze is fine for budget builds.
Modular vs semi-modular vs non-modular
**Non-modular**: All cables hardwired, cheapest, messy case wiring. **Semi-modular**: Some cables detachable, $20 extra, cleaner. **Fully modular**: All cables detachable, best cable management, $30–50 extra.
Best budget PSU: Thermaltake Toughpower (~$80)
650W, 80+ Bronze, semi-modular. Reliable, good cable management. Most popular budget option.
Best mid-range: Corsair RM850x (~$120)
850W, 80+ Gold, fully modular, Corsair reputation. Perfect for high-end builds ($1500+).