Analysis and comparison is presented as to processing performance levels with cutting speeds providing various optimization criteria: minimal cutting tool wear, minimal production cost and maximal cutting performance. It has been established that during machining at the cutting speed corresponding to the minimal cutting tool wear performance is close to the level of productivity when machining at the cutting speed corresponding to the minimal production cost. Results of calculations allow estimating both the performance value and the machinability level of different materials in terms of strength, not only in quality, but also in quantity. This assessment is made subject to the physical and mechanical properties of the work piece and the tool materials, the cutting mode (cutting speed and depth, feed), the tool geometry (cutter tip radius in the plan, cutting edge corner radius, face and clearance angles, major and minor cutting edge angles), as well as the economic performance of cutting (cutting time, cost of machine operation and labor cost, cutting tool operating cost).