Examkin

Soru

Zorluk: ZorMotherboards Form Factors and Connectors

A technician installs a secondary PCIe x4 expansion card into a desktop motherboard's second expansion slot. Immediately after booting the system, diagnostic software indicates that the primary PCIe x16 slot hosting the dedicated graphics card has dropped its operating link width from x16 down to x8 mode. Which of the following motherboard features or design characteristics is responsible for this behavior?

  1. PCIe lane multiplexing between expansion slots sharing CPU-attached lanesCevap
  2. B
    M.2 SATA keying fallback forcing interface protocol renegotiation
  3. C
    Single-channel RAM population triggering systemic bus throttling
  4. D
    Insufficient EPS12V power supply delivery to the motherboard PCIe bus

Cevap

PCIe lane multiplexing between expansion slots sharing CPU-attached lanes
Motherboards designed to support multiple high-bandwidth expansion slots often multiplex PCIe lanes connected directly to the CPU. When a secondary card is inserted into a shared slot, the motherboard automatically redistributes the available lanes, reducing the primary slot's width from x16 to x8 to supply x8 or x4 lanes to the newly occupied slot.

Adım Adım Çözüm

1
Analyze the observed hardware behavior
Populating a secondary PCIe slot causes the primary PCIe slot's link width to change from x16 to x8.
This is a characteristic symptom of motherboard PCIe lane reallocation or bifurcation.
2
Evaluate motherboard lane distribution design
Processor root complexes have a limited count of PCIe lanes (typically 16-24 direct CPU lanes). Motherboard manufacturers multiplex these lanes across multiple physical PCIe slots.
When the second slot is used, the motherboard splits the 16 primary lanes into two x8 channels so both slots remain active.

Anahtar Kavram

PCIe Lane Allocation and Slot Multiplexing
Bu soruyu puanla

Konular

Motherboards Form Factors and Connectors

Bu konudan daha fazla soru