I5 vs. i3 need help??

lately i have been looking into getting a laptop for school work and for helping my friend
design models for a small game design business we have began. i am having trouble
deciding which CPU i need i am going to be using model systems on it and my budget is
around 650$ which is why it is between the i5 and i3. i have looked into 2 specific computer
that i like but i am not sure what CPU is should get for my uses. the modeling programs
should not require to much processing power.

the programs are :
milkshape
ac3d
solid works
fps creator
realm crafter
minecraft

please help im a total noob when it comes to hardware