I upgraded my system on a B450-DS3H motherboard. The CPU changed from a Ryzen 7 1800X to a Ryzen 7 5800X3D, the GPU from an RX 550 to an RX 9060 XT 16GB, and the power supply from an unrated 700W unit to a Corsair 750W Gold model. I have four 8GB DDR4 sticks that worked normally before these upgrades. Now every stick works individually in the fourth RAM slot, but using any other slot causes the computer to repeatedly power-cycle without booting. I already tried clearing the CMOS by removing the motherboard battery, and the BIOS was updated for the new CPU. The CPU pins look straight. What should I check next?
3 Answers
Reseat the CPU and inspect the socket and CPU pins very carefully. On Ryzen systems, damaged or contaminated pins can disable an entire RAM channel even when the computer still starts with one slot. Look for bent or missing pins and any thermal paste in the socket. If necessary, clean contamination with high-percentage isopropyl alcohol and let everything dry completely before reinstalling it.
Try a complete CMOS reset again with the PC unplugged, then hold the case power button for 10–15 seconds before removing the battery for a few minutes. Afterward, test with one stick in the recommended slot, usually the second slot from the CPU. Four DDR4 sticks can be difficult for Ryzen memory controllers, but the fact that only one slot works points more toward a CPU socket, motherboard, or memory-channel problem. Also try slightly loosening the CPU cooler, since excessive mounting pressure can prevent some memory channels from working.
Since the CMOS reset was already attempted, I’d focus on testing one stick at a time and checking whether the second and fourth slots are the board’s preferred dual-channel slots.
Test with only two RAM sticks in the motherboard’s recommended paired slots, then test each slot individually. Make sure the modules are fully latched and that the BIOS is using default memory settings rather than an unstable XMP profile. If no configuration works outside the fourth slot after the CPU and socket have been checked, the motherboard is the most likely failure, though the new CPU’s memory controller could also be responsible.
If you still have the old processor, reinstall it as a diagnostic. If the old CPU also fails in the same slots, the motherboard or socket is probably the issue. If it works normally, the newer CPU may be defective or have damaged pins.