I am upgrading an HP Pavilion with Phenom x4 and NVIDIA GeForce, and 500G magnetic drive. Original memory was 4G DDR2 which I have upgraded to 6G but will go 8G before I am done. Also adding a 2nd drive, WD 1TB magnetic. As far as peripherals, I have an HP Photosmart printer, a Uniden security camera receiver, and use a 24" RCA LED LCD tv for a monitor, and powered external pc speakers. The current PSU is 300watt...will I need to upgrade PSU before adding the drive? If so, what would be recommended? thanks. I think my GeForce is 9150se.