I recently bought an 8GB Kingston Fury DDR4-2666 module for my Dell Latitude 3410. The laptop's original memory is an 8GB SMART 1Rx8 PC4-2666V-SO-DIMM. Each module works normally by itself, but installing both causes an extremely long delay before the Dell logo appears. The first boot also reports that the memory configuration has changed, and the system then fails to boot properly. Dell's built-in diagnostics report no problems. I updated the BIOS and cleaned the memory contacts, but neither helped. What could prevent these two modules from working together, and what should I buy or change to fix it?
3 Answers
A difference in CAS latency or other timing values may be contributing, but the laptop should normally choose common safe settings when possible. Kingston Fury memory can also be programmed with performance profiles that are less suitable for an OEM laptop than standard JEDEC memory. Check that both sticks are DDR4 SO-DIMMs using the same voltage and supported speed, and prefer standard JEDEC-rated memory rather than a gaming-oriented module. If possible, match the original stick’s rank and chip layout as well.
The modules are probably not compatible with each other, even though they have the same capacity and rated speed. Differences in timings, memory organization, rank, or the programmed JEDEC profiles can prevent a laptop from training both sticks successfully. The fact that each one works alone but not together points toward a compatibility issue rather than a dead module. The safest fix is to use a matched 2x8GB DDR4-2666 SO-DIMM kit, or buy another module with specifications that closely match the original Dell memory.
The long first startup is likely the firmware attempting memory training, which explains the delayed display and the memory-change warning. Since the BIOS is already updated and both modules pass individually, replacing the mismatched stick with a matched pair is the most practical solution. After installing the new memory, enter the BIOS, confirm the full 16GB is detected, save the settings, and run the diagnostics again.
That makes sense. I’ll replace it with a matched module or kit instead of trying to mix these two.