NIMCET 2021 — Computer PYQ
NIMCET | Computer | 2021Which of the following is the fastest means of memory access for
CPU?
Choose the correct answer:
- A. Registers(Correct Answer)
- B. cache
- C. Main memory
- D. Stack
Registers
Explanation
Memory Speed Hierarchy
The access time T for different memory types follows this inequality:
T_{\text{Registers}} < T_{\text{Cache}} < T_{\text{Main Memory}} < T_{\text{Secondary Storage}}
Comparison Table
| Memory Type | Location | Access Speed (Approx.) |
| Registers | Internal to CPU | 0.5−1 ns |
| L1 Cache | On-chip | 1−2 ns |
| L2/L3 Cache | On-chip / Near-chip | 3−15 ns |
| RAM | Motherboard | 50−100 ns |
| SSD/HDD | IO Bus | 10,000+ ns |
Final Answer
The fastest means of memory access is:
CPU Registers
Explanation
Memory Speed Hierarchy
The access time T for different memory types follows this inequality:
T_{\text{Registers}} < T_{\text{Cache}} < T_{\text{Main Memory}} < T_{\text{Secondary Storage}}
Comparison Table
| Memory Type | Location | Access Speed (Approx.) |
| Registers | Internal to CPU | 0.5−1 ns |
| L1 Cache | On-chip | 1−2 ns |
| L2/L3 Cache | On-chip / Near-chip | 3−15 ns |
| RAM | Motherboard | 50−100 ns |
| SSD/HDD | IO Bus | 10,000+ ns |
Final Answer
The fastest means of memory access is:
CPU Registers