ITPEC FE Morning April 2020 Question 11

SRAM vs DRAM — compare memory types by structure and refresh behavior.

SRAM (Static RAM):
- Uses flip-flops (6 transistors per bit)
- No refresh needed — data retained while powered
- Faster, more expensive, lower density
- Used for: cache memory

DRAM (Dynamic RAM):
- Uses capacitor + transistor (1+1 per bit)
- Requires periodic refresh — capacitors leak charge
- Slower, cheaper, higher density
- Used for: main memory (RAM)

Key differences:
- Refresh: SRAM = none, DRAM = required at fixed intervals
- Transistors per bit: SRAM = more (~6), DRAM = fewer (1)
- Cost: SRAM > DRAM
- Speed: SRAM > DRAM
- Density: DRAM > SRAM

Why not others:
- (a) SRAM consumes less idle power (no refresh cycles)
- (b) SRAM needs more transistors per bit, not fewer
- (d) Descriptions are swapped — DRAM uses capacitors+transistors, SRAM uses flip-flops

AI-generated — may contain errors