The higher the clock speed, the faster an individual application can execute. The more cores, the faster both multi-threaded applications and multiple applications running simultaneously can execute. For normal “workstation” use, higher clock speeds are better than more cores. For “server” use, where many applications may be running simultaneously or where multi-threaded applications may be run, more cores is better. Examples of multi-threaded applications include web servers (apache) and video rendering software (kdenlive).
When finished selecting your Processor, proceed to Step 3 – Memory.