220-1101 Question 246
Single answerPeripheral Component Interconnect Express (PCIe)A technician is upgrading a desktop workstation with a new PCIe x16 graphics card. After opening the case, the technician sees that the motherboard has one PCIe x16 slot already occupied by a RAID controller, one open PCIe x1 slot, and one open PCIe x16-length slot that is electrically wired for x4. The user wants the best graphics performance possible without replacing the motherboard. Which action should the technician take?
- A
Install the graphics card in the open PCIe x1 slot by using a physical adapter so the card can still run at full speed
- B
Move the RAID controller to the PCIe x1 slot and install the graphics card in the full PCIe x16 slot
- C
Install the graphics card in the open x16-length slot wired for x4, understanding the card will function but may have reduced bandwidth
- D
Install the graphics card in the x16-length x4 slot and disable ECC in BIOS to increase PCIe lane availability
Show answer and explanation
Correct answer: C
Explanation
PCIe slots can have both a physical size and an electrical lane configuration. A slot may be physically x16 in length but electrically wired as x4. In that case, a PCIe x16 graphics card will often still work because PCIe supports lane negotiation and backward compatibility across lane widths, but the card will operate with the bandwidth of the electrical connection, not the physical connector length. For A+ Core 1, candidates should understand the practical difference between mechanical fit and electrical capability when installing expansion cards. Best practice is to verify motherboard documentation for slot wiring and lane sharing, because motherboard manuals commonly specify whether a slot is x16 physical/x4 electrical and whether lanes are shared with storage or other onboard devices.
- A. Incorrect.
Incorrect. A PCIe x1 slot does not provide the lane count needed for full x16 graphics bandwidth. While PCIe is scalable and some adapters or modified installations may physically fit in unusual situations, this is not an appropriate or standard way to achieve full graphics performance. The misconception is that physical compatibility guarantees full electrical performance.
- B. Incorrect.
Incorrect. A RAID controller designed for a larger PCIe slot cannot simply be assumed to work correctly in a PCIe x1 slot. Even if the card could physically fit, the x1 slot provides far fewer lanes and may not support the controller's bandwidth or physical connector requirements. The option is attractive because it tries to free the full x16 slot, but it ignores slot size and lane requirements.
- C. Correct.
Correct. A PCIe graphics card can typically operate in a longer slot that is electrically wired for fewer lanes, such as x4, as long as the motherboard and card support standard PCIe negotiation. However, the card will have less available bandwidth than in a true x16 electrical slot, which can reduce performance. In this scenario, this is the best available option without replacing the motherboard or removing the existing card from the true x16 slot.
- D. Incorrect.
Incorrect. ECC settings relate to memory error correction, not PCIe lane allocation. Disabling ECC does not free PCIe lanes for expansion slots. This distractor reflects a common misunderstanding between motherboard resource settings and PCIe lane distribution.