Why Direct memory access has priority over the CPU when both request a memory transfer?

we can transfer data direct to and from memory without the need of the CPU. The transfer of data between a fast storage device such as magnetic disk and memory is often limited by the speed of the CPU. Removing the CPU from the path and letting the peripheral device manager the memory buses directly would improve the speed of transfer. This transfer technique is called direct memory access(DMA). During DMA transfer, the CPU is idle and has no control of the memory buses. A DMA controller takes over the buses to manage the transfer directly between the I/O device and memory.

With Regards.

Veer Thakur.

Chandigarh.