I don't think the RTX 5090 will be as power-hungry as that, though, and I really think that the two 12V-2x6 power sockets on the AI1600T PSU are just for multi-GPU setups handling AI workloads ...
The RMx Series, a family of low-noise PC power supplies that maker Corsair has ... including ATX 3.1 compliance, a native ATX 12V-2×6 connector, and a manual fan speed control knob, Corsair ...
The newer USB Power Delivery Programmable Power Supply (USB PD PPS ... This version supports 10W (5V, 2A), 18W (12V, 1.5A), 36W (12V, 3A), 60W (12V, 5A), 60W (20V, 3A), and 100W (20V, 5A) of ...