Pipelining is a CPU design technique that improves performance by introducing parallelism. It allows multiple instructions to be executed simultaneously, thereby increasing the overall throughput of the CPU. This is achieved by breaking down the execution of instructions into smaller stages and overlapping them.

- Reduced memory access time:
Pipelining can help reduce memory access time by overlapping the fetch and execute stages of different instructions. While one instruction is being executed, the next instruction can be fetched from memory, reducing the idle time of the CPU. This overlapping of memory access and execution stages helps to hide the latency of memory operations, resulting in improved performance.

- Increased clock speed:
While pipelining does not directly increase the clock speed of the CPU, it can indirectly improve performance by allowing for a higher clock frequency. With pipelining, the CPU can make better use of the available clock cycles by executing multiple instructions in parallel. This means that the CPU can achieve a higher instructions per cycle (IPC) rate, effectively achieving a higher throughput without increasing the clock speed.

- The introduction of parallelism:
The key benefit of pipelining is the introduction of parallelism. By breaking down the execution of instructions into smaller stages, multiple instructions can be in various stages of execution at the same time. Each stage of the pipeline performs a specific operation, such as instruction fetch, decode, execute, and writeback. This allows for overlap and simultaneous processing of multiple instructions, resulting in improved performance.

- Additional functional units:
Pipelining can also take advantage of additional functional units in the CPU. Each stage of the pipeline can be assigned to a separate functional unit, allowing multiple instructions to be processed simultaneously. This effectively increases the CPU's processing power and enables higher throughput.

Overall, pipelining improves CPU performance by reducing memory access time, introducing parallelism, and taking advantage of additional functional units. By overlapping the execution of instructions and allowing for simultaneous processing, pipelining increases the CPU's throughput and improves overall performance.