How the cpu works?

The trend towards lower supply voltage therefore works against the goal of high clock speed. Only improvements in photolithography and reduction in threshold voltage allow both to improve at once. On another note, the formula shown above is for long channel MOSFETs. With the area of the MOSFETs halving every 18-24 months (Moore's law) the distance between the two terminals of the MOSFET switch called the channel length is becoming smaller and smaller. This changes the nature of the relationship between terminal voltages and current.