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Difficulty: Very hardMotherboard, RAM, CPU, and Power Issues

A desktop technician is troubleshooting an custom-built audio workstation that intermittent fails to complete POST, emitting three long beep codes during cold boots. When the system does successfully boot into the operating system after multiple power cycles, it operates normally during low-memory tasks, but crashes with memory-address exception errors when running multi-track recording sessions. Upon physical inspection, the technician observes that two identical 16 GB DDR4 RAM modules are installed in adjacent slots (Slot 1 and Slot 2, corresponding to Memory Channel A only), leaving Memory Channel B completely empty. Which of the following describes the root cause of this failure and the correct diagnostic resolution?

  1. The memory modules are incorrectly populated across a single channel, causing timing instability and memory detection POST errors; move one module to Slot 3 (Channel B) to populate memory across separate channels as specified by the motherboard architecture.Answer
  2. B
    The three long beep codes indicate catastrophic BIOS corruption during cold power sequencing; flash the motherboard UEFI firmware to the latest revision using a USB recovery drive.
  3. C
    The power supply unit (+12V rail) is failing to deliver sufficient continuous wattage to the memory controller during high load; replace the power supply unit with a higher wattage model.
  4. D
    The motherboard requires SO-DIMM memory modules rather than standard unbuffered DIMMs; replace both installed modules with SO-DIMM form factor memory.

Answer

The RAM modules are improperly installed in single-channel slots rather than dual-channel configurations; moving one RAM module into Slot 3 (Channel B) enables dual-channel architecture and resolves memory initialization errors.
The system's three long beep codes indicate a memory failure during POST, caused by installing matching memory modules into adjacent slots (Channel A only). Motherboards designed for dual-channel operation require RAM modules to be populated across alternating slots (Channel A and Channel B) to establish proper bus timing and channel initialization. Moving one module to Slot 3 enables dual-channel mode and fixes both cold-boot POST failures and memory exception crashes under load.

Step-by-Step Solution

1
Analyze reported symptoms and physical hardware configuration.
Three long beep codes during POST indicate a memory initialization or detection error. Two RAM modules are installed in adjacent slots (Slot 1 and Slot 2), which belong to the same channel (Channel A).
Motherboards require memory modules to be distributed across designated dual-channel slots (e.g., Slot 1 and Slot 3) to properly balance memory bus loading and timing signals.
2
Evaluate the impact of single-channel population on dual-channel motherboards.
Improper channel population forces the memory controller into asymmetrical channel access, leading to POST beep codes, memory timing instability, and crash errors under heavy memory utilization.
Dual-channel memory architectures require matching modules installed in alternating slots to function within proper electrical signal tolerances.
3
Determine the corrective action.
Relocate one memory module from Slot 2 to Slot 3 (Channel B, Slot 1).
This establishes proper dual-channel channel population according to motherboard manufacturer guidelines, eliminating POST beep codes and memory crash exceptions.

Key Concept

RAM Channel Population and POST Diagnostic Indicators
Estimated Time:1m 30s
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Topics

Motherboard, RAM, CPU, and Power Issues

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