RAM

Week 4 · Module 4: RAM · Download .docx

Objectives

Distinguish DDR4 and DDR5 RAM specifications
Explain and configure dual-channel memory
Identify DIMM vs SO-DIMM form factors
Describe ECC RAM and its use cases

Key terms

Volatile: Loses all data when power is removed — the defining characteristic of RAM.
DDR4: 288-pin desktop DRAM at 1.2V, 2133-3600+ MT/s.
DDR5: 288-pin next-gen at 1.1V, 4800+ MT/s, on-die ECC.
Dual-channel: Two matched DIMMs in alternating slots — doubles effective bandwidth.
ECC: Error-Correcting Code RAM — detects and corrects single-bit errors; required in servers.

The concept

RAM is the system's working memory — data and instructions in active use live here. Unlike storage, it is volatile: power off means all data is lost. DDR4 and DDR5 are the two current desktop standards; DDR5 adds speed, lower voltage, and on-die ECC. Installing RAM in dual-channel configuration (matched pair in alternating slots) doubles the effective memory bus width, improving performance in memory-intensive tasks. ECC RAM adds extra bits to detect and correct single-bit errors — essential in servers, unnecessary overhead in consumer PCs. Always enable XMP/EXPO in BIOS to get the DIMM's advertised speed.

Worked examples

Example 1: [object Object]

Common mistakes

Installing both DIMMs in adjacent slots 1+2 — creates single-channel mode.
Not enabling XMP — RAM defaults to JEDEC 2133 MHz even if rated 3200+.
Forcing a DDR5 stick into a DDR4 slot — different notch positions; forced insertion damages both.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. 'Volatile' means RAM does what?

2. Which RAM form factor is used in laptops?

3. Dual-channel RAM configuration provides what benefit?

4. ECC RAM is required in which environment?

5. To run DDR4-3200 at rated speed, which BIOS setting must be enabled?

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