The answer by Fang Li is correct. For every technology node, like 16nm for example, there are different libraries with cells that are optimised for low power, fastest speed or smallest area. But it is always a trade-off between those factors. The threshold voltage is one of the important parameters that influence speed, power and area.
What is the difference between LVT HVT and SVT cells in VLSI (layout level explanation would be better)?