ITPEC FE Morning April 2019 Question 10

SRAM vs DRAM — compare memory characteristics at the same semiconductor process.

SRAM (Static RAM):
- Uses 6 transistors per cell (flip-flop circuit)
- No refresh needed — data held as long as power is on
- Faster, more expensive, lower density
- Used for CPU cache (L1, L2, L3)

DRAM (Dynamic RAM):
- Uses 1 transistor + 1 capacitor per cell
- Requires periodic refresh (capacitor leaks charge)
- Slower, cheaper, higher density
- Used for main memory (RAM sticks)

Why not others:
- (a) SRAM consumes less power when idle (no refresh needed)
- (b) Both are volatile — data lost when power is off
- (c) Reversed — DRAM needs refresh, not SRAM

Key rule: SRAM = more transistors, faster, costlier, no refresh. DRAM = fewer transistors, cheaper, needs refresh.

AI-generated — may contain errors