9800GTX+ not enough power?

[norco kid]

I just installed a 9800GTX+ in my computer and as soon as it boots up a power warning shows up. I have a Raidmax Smilodon case that came with a 500W PSU. I used an available 6 pin connector from the PSU to one of the power inputs on the card. I assume the other one needs power aswell, but I have no more available 6 pin connectors. In the box, the card came with a y from 2 4 pin connectors to a 6. Should I use this Y connector to power the other power input on the card? Do both of the 4 pin connectors on the y need to be plugged in to power from the PSU?

 

[foxyg]

what does the warning say?