The 4720 is a 4 CPU cores and eight threads of process regarding the 2 cores and 4 threads that i5 give a significantly higher performance in situations where a 100% CPU used.
Examples of intensive tasks are:
A video rendering where all cores working at 100% to create the video from the project or assembly. In this case notaries quite i7 performance and would end the task well before an i5.
In next-generation games that take advantage of multicore yes you could get to have some improvement and get some extra fps, even putting extreme situation of a game that has as a minimum requirement where 4-core CPU is required, the i5 would stay here insufficient. Anyway in most current games the performance difference is negligible, and those who make use of the CPU would lose some more fps can always recover some sacrifice in graphic quality of the game.
The above two situations are unique processes that require a lot of computing power and thus consume much CPU but can also be the case that instead of a 'heavy' process you have several less demanding process but the sum of these come to cause Maximum CPU demand. Obviously browsing, listening to music and typing text (for instance multitasking) you will not reach 100% of your i5 so little improvement compared to i7 notaries in most cases. That i5 is capable of carrying fluently SO and several programs simultaneously without compromising performance.
On the other hand it is not far-fetched that CPU upgrade later by a i7 (I've done with my current laptop) especially if you are short on budget and not fit you spend those 200 € more it costs the i7. Surely if you invest half of that money on an SSD you will notice an improvement in performance and overall fluency much higher than if you had the i7.