CPU 4nm, 3nm, 2nm difference. Is processor with lower NM better?

What is the difference between phone CPU with 4nm, 3nm and 2nm ?

What is the meaning of NM ?

Is processor with lower NM better ?

NM is an abbreviation of nanometer, which is a unit of length. One nanometer equals to one billionth of a meter:

1 nm = 0.000000001 meters

Nanometer is used to measure the size of transistors (semicondutors) and some other components on a CPU chip.

As technology advances, transistors can be made smaller, what makes CPUs better, because of several benefits. So, the lower NM generally means better CPU.

The advantages of CPUs with smaller transistors are:

• Power efficiency increase - smaller transistors need less electricity to do the same tasks.
• Heat output reduction - smaller transistors generate less heat. Less heat means lower electrical resistance, so electricity flows better. Less heat also means less cooling is required.
• CPU size reduction - smaller transistors mean the CPU size can be reduced, or there can be more transistors in the same-sized chip.
• Performance increase - there are multiple factors that have an impact on CPU performance. First, higher temperature slows down the CPU. The less heat mean the CPU can perform faster. Second, in case of the smaller size of transistors there is a lower distance between them, so the electric signal flows faster. Third, higher transistor density means more transistors can fit in the same space, so the overall performance can be better.

The impact of using of smaller transistors can be significant. For example in 2010, the common transistor size was 32 nm. In 2020, the common transistor size was 5 nm, what is 6 times less (600% reduce).

Today, the common transistor size is 4 nm and 3 nm. Some companies have announced future production of CPUs with 2 nm transistors.

Lower NM means smaller sized transistors, what means higher energy efficiency, so less electricity is needed, so the phone batteries can be smaller and lighter.