Which is better Intel core2 to dueo or AMD phnom X3 triple core?

This depends. There are different types of Intel core 2 duo processors and AMD phenom X3 processors. Intels generally run cooler, but they are expensive and suspectible to hardware failure when you overclock them. AMD processors run hot but will keep running until the computers shuts it down. They are often cheaper than intels and better value. Currently, Intel is leading the way in processor technology. Its a preference and there are trade-offs