Corsair, the most awarded PC power supply brand in the world1, today announced the new line of CS Series Modular power supplies (PSUs) in 450, 550, 650 and 750 watt models. Designed to be exceptionall... Corsair CS Series Modular PC Power Supplies
Why non-24/7? Because of the sleeve bearing fan, I guess. As for single GPU; I would think the 650 or 750W should be able to handle a pair of GPUs no problem.