Only the best PSU for the RTX 3090 will do; NVIDIA's new flagship graphics card won't fare well with underpowered or ancient power supply units (PSU). They can lead to crashes and overall system instability, and if you're shelling out more than a grand on new hardware, you don't want to skimp elsewhere. NVIDIA recommends a 750W PSU for the RTX 3090, which is what we'll focus on in this collection.