The GTX460 Hawk has a 7+1 phase PWM design, which means that it adjusts it's power usage to match performance demands. The LED lights show which phase the card is currently in. All lights will be lit when the card is in full gaming performance mode.
"Once powered on you can see little LED lights on the card, these are Phase LEDs and show the activated power phases. When clocked down for example only 4 will lit up. Fun to see, mostly there for aesthetics."http://www.guru3d.com/article/msi-geforce-gtx-460-hawk-review/1