StarTech ATX2PW550WH 550W

A 550W unit with 80+ efficiency certification and non-modular cabling. It uses the ATX form factor — confirm your case lists ATX support. 550W covers mainstream builds with a modest GPU. Power supplies are the wrong place to cut corners — efficiency certification correlates with build quality and warranty length.

PlanMyPC's builder flags compatibility problems automatically and tracks the latest power supply deals from multiple stores. Support and warranty service run through StarTech, with terms that vary by region. Scroll down for the complete spec table; the builder's compatibility checker will warn you about any conflicts with components you have already picked.