Sadly enough I do not overclock so I do not have any info for the overclock part for you, but I must admit the C6300 is a VERY nice chip for the price, I do not have it myself but I am going to be in the process of selling myh current machine to some kids I know in high school at the moment then purchase a 6300 or 6400 with a decent Mobo and probably a 7900GT.
Basically, if you can handle it I would go with the Conroe, will be in use long after the X2 dies out.
P.S. I went from a 2001 HP computer I purchased which came with a Geforce 4 which I upgraded to a Geforce 5200 my brother gave me to my current rig, Man, no telling what two generations of video cards do for you lol.
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