Not only do you want the larger power supply to meet the higher power demmands, but you need to make sure that the power supply has enough output on the 12volt rail to support the new processor. New AMD's are power hogs on the 12v supply of a power supply. Also, a cheap power supply now could end up killing your processor prematurly by sending it dirty power; that is power that is not a stable 12, 3, 5, volts all the time.
I know you say you are not a gamer, but that onboard video will be a huge resource hog on both your processor and ram. You might want to consider getting a cheap video card, like a 9800pro; let a video card do the video work, and let the processor do it's job.
