Difference Between Primary and Secondary Memory

Primary Memory	Secondary Memory
It is also called main, internal, or system memory.	It is also called auxiliary, external or backup memory.
It holds data, programs, and information that are currently under execution.	It holds data, programs, and information permanently.
It is directly accessible to the CPU.	It isn’t directly accessible to the CPU.
It can’t be used for carrying data from one computer to another.	It can be used to transfer data from one computer to another.
It is usually a volatile memory except ROM.	It is a non-volatile memory.
It is faster for reading/writing operations.	It is slower for reading/writing operations.
It is used in smaller storage capacity in PC.	It is used in larger storage capacity in the PC.
It is usually an expensive per-bit cost.	It is usually cheaper at a per-bit cost.
It is on the top level of the memory hierarchy.	It is on the low level of the memory hierarchy.
It is the part of the motherboard.	It is the external media attached to the motherboard.
For eg: RAM, ROM, cache memory.	For eg: Hard disk, CD, DVD, pen drive, etc.