core i7 is faster in some applications which uses all processor/core. i3 currently supports dual processor both with dual core. This means running 4 2.5GHz clock at the same time. While i7 supports quad processor all with dual core. Means running 8 2.2Ghz clock at the same time. Again it varies with the application that would be using the processor. If the application is only using a single thread then the i3 is faster. If it uses multiple threads then i7 is faster.