Rough idea:
If doing exactly 1 thing, the core is about as fast as a turion at the same clock speed.
If doing 2+ things at once then the core is twice as fast.
Some applications written to use 2 cores go faster even by themselves but most do not.
If you need any 3D power, also compare video, since it usually isn't upgradable. nvidia 6100/6150 integrated isn't great, but it's still much better than intel craphics.