Intel core i3 vs i5

Hello,

I've just bought a new laptop. I paid a wee bit extra for a core i5 processor as opposed to i3. However, I am considering returning it, as I have realised that the laptop version of i5 is also dual core, not quad, as in most i5 processors in desktops.

Hence my question is, is there any real difference between these two types of processor, or is it a bit of a gimmick in this regard? I could have saved around £80/90 going for a computer with an i3 chip (also latest 'sandy bridge' chip), which has the same GHz, L3 Cache and number of cores!


Thanks,

Tom