what is the advantage of using a CPU register for temporarydata storage over using a memory location?

Question

what is the advantage of using a CPU register for temporary data storage over using a memory location ?

Answer 1

• registers are accessed usually in 1 cpu cycle (.3 nano-seconds).
• L1 Cache access is .5 nano-seconds
• L2 cache access is 7 nano-seconds
• DRAM access is 200 nano-seconds.

So you are about 600x faster with registers than working with ram.

Speeds referenced from here.