The cards measure the current at the supply plugs and thus limit the GPU. With overclocking tools, depending on the card, you can still correct the power limit upwards (depending on the manufacturer and card between 10-30%, 20% for this card here as far as I know). If you want to feed even more current to the card, you have to outsmart the measuring circuit (soldering on the 1400 graphics card!). Certainly not recommended if you have no soldering experience and don't know exactly what you're doing). From what I've heard, the card can be boosted to 600W with the appropriate modufications, but even the cooling system won't eat that up...