If the CPU does not matter for 3D modeling software, then you would not have been reading this software. The choice of a good CPU is highly critical as a slower CPU will highly affect the way you work. You might get frustrated when using a CPU with lower power. Your computer may not even be able to run the desired software, or may eleven crash. Therefore, it is proved that the choice of a CPU for blender and AutoCAD is of paramount significance, and you should choose your CPU with care.