Question

Which of the following is a key reason for choosing DRAM over SRAM for main memory?

• A. DRAM requires fewer transistors per bit than SRAM
• B. DRAM is faster than SRAM
• C. DRAM consumes less power than SRAM
• D. DRAM is non-volatile, unlike SRAM

Hint:

A DRAM cell is one transistor plus a capacitor, giving higher density than SRAM's six-transistor cell.

Answer 1

The Correct Option is A

Step 1: Compare the storage cells. A DRAM cell stores one bit using a single transistor and a tiny capacitor, while an SRAM cell needs about six transistors arranged as a latch.

Step 2: Because a DRAM cell uses far fewer transistors per bit, many more bits fit in the same chip area. This higher density makes DRAM cheaper per bit and ideal for large main memory.

Step 3: Check the wrong options. SRAM is actually faster than DRAM, so (B) is false. DRAM must be refreshed constantly, so it does not clearly use less power for main memory, making (C) misleading. Both DRAM and SRAM lose data when power is removed, so (D) is false because DRAM is not non-volatile.

Step 4: The correct key reason is the smaller cell, so option (A) is right.