If the data your program needs are stored in the main memory, then they can be accessed in $0$ cycles during the execution of the instruction. If stored in a disk, $4$ to $75$ cycles. If stored in registers, hundreds of cycles. And if stored in cache, tens of millions of cycles

If the data your program needs are stored in main memory, then they can be accessed in $0$ cycles during the execution of the instruction. If stored in a cache, $4$ to $75$ cycles. If stored in registers, hundreds of cycles. And if stored in disk, tens of millions of cycles

If the data your program needs are stored in main memory, then they can be accessed in $0$ cycles during the execution of the instruction. If stored in a single cache, $4$ to $75$ cycles. If stored in registers, hundreds of cycles. And if stored in multilevel cache, tens of millions of cycles

If the data your program needs are stored in a CPU register, then they can be accessed in $0$ cycles during the execution of the instruction. If stored in a cache, $4$ to $75$ cycles. If stored in the main memory, hundreds of cycles. And if stored on disk, tens of millions of cycles