Question

How does the use of registers improve system performance?

Answer 1

registers as in processor registers or Windows registers ?
i assume its processor's registers ....
usually we program in higher level languages like c,c++ ,java etc ..
these lanaguages are all converted into bytecodes or executables by their respective compilers ... .which are ultimately converted to binary codes which is the only possible input to processor in your pc ..
so these higher level language compiler convert code into pre-defined binary which may not be suitable for your purpose and might become large amount of redundant code ..coding in machine level language or assembly gives you the complete control over your pc but code development is tedious ... whilw codin in higher languages is simpler but you lose precise control over your processor ..so choosing between languages of programming is usually a compromise between these 2 parametes ...

Answer 2

Registers are memory close to the processor, usually on the chip, and which have logic circuitry associated with them so that the registers can be incremented, added together and so on. Contrast with external memory. A typical operation written in a programming language might be C = A + B. Implemented in machine language, it becomes this:

Fetch value of A from memory into register 1.
Fetch value of B from memory into register 2.
Add contents of register 2 into register 1.
Store value of register 1 into memory C.

The fetch and store operations usually take more time than the addition operation.

If you have several registers in your processor, say 8 of them, you can keep various intermediate results around, and do something complicated without having to wait for memory. For example, computing the value of a polynomial expression. One fetch for X value, one fetch for each coefficient, and one store for the result. All the other work, such as calculation of X^n for some n, and accumulating the partial sums, can be done on the processor chip if there are enough registers.

Answer 3

Use of registers neither improve system performence nor makes your programs run faster because they are memories of your CPU.