I depends on your PC/Workstation.
To be more precise, previously, rendering was dependent solely on your CPU, so more powerful CPU meant less rendering times.
Also, more cores of CPU = better effeciency at rendering and multitasking, which is why budget workstations often tend to opt for AMD's Ryzen processors. They have more cores compared to their INTEL counterparts. But INTEL provides us with more single power performance.
MODELLING = DEPENDS ON SINGLE CORE PERFORMANCE
RENDERING = MORE CORES BETTER PERFORMANCE.
So, its completly upto the user.
But right now the hot topic is CUDA CORES(GPU RENDERING). The timings are slashed by more than 10 times as compared to CPU rendering. So, at least a second hand 750Ti would be recommended for starting up, later you can upgrade to more better cards.