Replaced my Nvidia 5700 with a 6600. When I boot up, Windows displays OK but I get this message:"Nvidia has detected that there is not enough power for this graphic card and has adjusted to a lower setting".Is this a power supply problem or my motherboard and chip are not enough speed.ThanksEd2.4 gigNvidia 6600

The 6600 has a separate power connector and requires to be plugged into the the power supply on a clean feed (one not shared with anything else). You have forgotten to plug it in, as the 5700 took its power from the mobo.Allcott