Optiplex 9020 RAM offers impressive performance.
Optiplex 9020 RAM offers impressive performance.
Check if the bios contains an event log. If present, clear it, save, and close bios. Alternatively, after entering bios after a prompt, save before exiting—even without changes—to see if that resolves the issue.
Poor connections can lead to unusual behavior in memory storage.
Dells doesn't always follow the official guidelines. I understand the theory if you're in Slots 1 and 2 with Matched Pair A, and in Slots with Matched Pair B, it should function as long as neither pair breaks the rules—even if A and B aren't identical. But my real-world experience with Dells suggests otherwise. I'd align with others who say you can clean the RAM slots, re-seat the CPU, and just hope. Ideally one of those adjustments would fix it. However, if you manage to boot using Pair A or Pair B but not both, it might mean you need to replace one pair in favor of four identical ones. I've encountered this situation often, so I usually upgrade memory for Dell using the Crucial tool: https://www.crucial.com/store/advisor. The truth is, if Dell never released a configuration like 2x4, 2x2, they likely didn't test it properly. Or perhaps they did, but timing issues in the BIOS—like forced down-clocking to the slowest speed—cause problems. At least 20% of the time I've had issues trying exactly what you're suggesting.
I processed the BIOS log, then inspected, cleaned, and repositioned the CPU. Applied fresh thermal paste, cleaned RAM slots thoroughly, and polished module pins. Reassembled everything carefully. Verified proper placement. Restarted the system. Successfully ran F1 to start, F2 into setup, F5 for diagnostics. Selected F5. Memory tests passed all checks. After exiting and rebooting, the same issue reappeared. Single beep repeated consistently. I believe it’s correct. 8GB should suffice at this stage (I don’t consider myself a gamer in the future).