Graphics Card issue - Nvidia

[Viki]

I just installed an Xtravision 256mb Geforce 6600GT, and when i switched the PC back on after putting it inside, it said after installing the drivers, something like (will detect best settings, not enough power going to graphics card) or something, so I'm thinking, did I forget something? There was a lead, like the ones that go into the back of the HD, it came with the graphics card. So, is my card only working at a certain performance level now? Do I need to connect that lead to something? It seemed okay when I played a game, although the rest of the parts in the PC don't really match the card.. Another question, the old card was a Geforce Ti4600, which was playing up I think, is the card I have now, way better than that, or just a little better?

[TechZ]

The newer graphics cards require a direct connection from the PowerSupply into the card as well.

There was a lead, like the ones that go into the back of the HD, it came with the graphics card.

Unless you connect the 6600GT to your PowerSupply via the supplied lead, its going to run at reduced performance. Much lower than what it can actually do.

[Viki]

you rock, thanks. one more thing, let's say I connect the lead to the power supply, then I switch my PC back on, how do I tell the Graphics card to start running at proper levels again? Which settings? Or will it be automatic?

Also, there's 3 on the cable, is one not needed?