Not the chip you want, but I'm pretty close, and X2 works fine:
Intel Core 2 Duo E8400 3.00 GHz
X2 seems to be a little lighter load than X1 was, but that's only intuitive.
Coincidentally, I just installed Sibelius 7 last week. That was the first software I've encountered that listed Core 2 Duo as the minimum hardware requirement. Probably time for me to build another PC.