I'm building a new PC with a Ryzen 7 9800X3D, an MSI PRO X870E-P motherboard, and G.Skill Flare X5 memory purchased as a bundle. The first set of parts would not post with both RAM sticks installed in slots 1 and 3. After removing one stick and moving the remaining stick to slot 2, it posted once, but never again. I returned the bundle and received replacement parts, yet I'm having the exact same problem. Right now it has posted with only one RAM stick installed in slot 3, but it previously failed to post. I've built several PCs before and haven't encountered this kind of inconsistent behavior. What should I check?
4 Answers
Confirm that the motherboard firmware supports the Ryzen 7 9800X3D. A new board would normally be expected to support it, and successfully reaching the BIOS once is a good sign, but checking the BIOS version and updating it if necessary can rule out compatibility issues.
Check the motherboard manual for the exact DIMM slots to use and follow that layout rather than relying on the slot numbers alone. On some systems, using the wrong pair can prevent the CPU from initializing the memory properly. Also, don’t interrupt the first few boot attempts because memory training can take several minutes.
Since changing the RAM slots appears to affect whether it posts, start with the memory configuration rather than replacing more parts. Test one stick at a time in the recommended second slot, then add the second stick to the fourth slot. If one particular stick or slot consistently fails, that can help identify whether the issue is the DIMM, motherboard, or CPU memory controller.
Install the memory in the motherboard’s recommended primary slots, which are usually slots 2 and 4 when using two sticks. Clear the CMOS afterward, power the system on, and give it plenty of time to complete memory training. AM5 systems can take a while to post after changing RAM.
That worked! It posted again after moving the memory and clearing the settings.
If it still fails, clear the CMOS again and let the system sit through the full memory-training process before assuming it is stuck.
The board is brand new, and I was able to boot into the BIOS once, so I assumed the firmware supported the processor.