What is the compatibility of DDR3 and DDR4 DIMMs in the same HP workstation?

Question

Options

• AThe system must have at least 2 DDR4 DIMMs to one DDR3 DIMM.
• BThe system must have either all DDR3 DIMMs or all DDR4 DIMMs.
• CThe system can have any number of DDR3 and DDR4 DIMMs
• DThe system must have at least one DDR3 DIMM to one DDR4 DIMM.

• A
  3% (1)
• B
  3% (1)
• C
  89% (31)
• D
  6% (2)

Explanation

Heads up: the answer key appears to be incorrect. Option C is factually wrong, and explaining it as correct would give you bad information for the exam and real-world practice.

The actual correct answer is B.

DDR3 and DDR4 are physically incompatible - they use different pin counts (240-pin vs. 288-pin), different voltages (1.5V vs. 1.2V), and different notch positions. A DDR4 DIMM literally cannot be inserted into a DDR3 slot, and no HP workstation supports mixing both generations in the same system.

Why the distractors are wrong:

• A and D fabricate specific ratios (2:1, 1:1) that don't exist - no such mixed configuration is possible.
• C is the trap answer here; it implies free mixing, which is physically impossible.

Memory tip: Think "generation lock" - just like USB-A and USB-C ports won't accept each other's plugs, DDR3 and DDR4 slots are generation-locked. One system, one generation.

Recommendation: If this came from an official HP exam or study guide, double-check the source material - this may be a typo in the answer key (C and B are adjacent choices and easy to mix up). If your exam insists the answer is C, flag it with your instructor, as it contradicts how RAM physically works.

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