I have owned a x2 and unless you are ocing, the chip is not very powerfull. It runs at 2.0ghz. Just to put some perspective on it, my kids 3400+ 754 is faster than my 3800 x2 was.
I went from 3000+ winchester to the 3800 x2 manchester, at stock, and was not impressed. The only differance I noticed was when I encoded my dv to dvd, then it was twice a fast as my 3000+, but game and all around everyday performance was just a tad faster, if any!
Just my opinion, please do not flame!