I built this PC for a friend about one to two years ago, and it has recently started turning on and off repeatedly without ever reaching the BIOS. The system uses a Ryzen 5 7600X, an MSI B650 Gaming Plus WiFi motherboard, an ASRock RX 5700 XT, four 16GB DDR5-5200 Kingston Fury modules, a Kingston NVMe drive, a 2TB SATA SSD, and a Corsair RM650 power supply.
I tested the system with the monitor connected to the motherboard's video output, removed the dedicated GPU, reseated both storage devices, cleared CMOS, reseated the RAM and GPU, checked every cable, and cleaned the connectors. I also removed and reseated the CPU and cooler. None of that changed the behavior.
The motherboard's debug LEDs have shown different faults at different times: usually the white GPU light, sometimes the yellow DRAM light, and occasionally the red CPU light or red-and-yellow together during apparent memory training. The machine never stays on long enough to enter BIOS. I also tried another known-working GPU, but that didn't help.
I'm wondering whether the four-stick DDR5 configuration could be causing failed memory training, or whether the motherboard itself has failed. I don't currently have another DDR5 system available for testing. What would be the best diagnostic sequence from here?
2 Answers
Use the motherboard’s BIOS Flashback feature before replacing parts. It can reflash the BIOS without successfully booting into setup, and it may recover a system stuck during memory training. Follow the manual’s exact USB formatting, file-naming, port, and button instructions; if the flash fails immediately, try a different small USB drive.
A POST diagnostic card can provide additional codes, but the one-stick memory test and BIOS Flashback are more useful first steps. If the board still power-cycles with no storage, no GPU, and one known-good stick, testing with a different power supply would be worthwhile, followed by replacing or warranty-testing the motherboard.
Start with the memory and reduce the system to the bare minimum. Remove the motherboard from the case to rule out a short, disconnect all storage and the GPU, and leave only the CPU, cooler, 24-pin power, CPU EPS power, and one RAM stick in slot A2. Clear CMOS properly, then give the first boot several minutes because AM5 memory training can leave the screen blank for a while.
Test each stick individually in A2. If one stick allows the system to POST, enter BIOS, disable EXPO or XMP, and try running the memory at a conservative JEDEC speed. Four DDR5 modules put much more stress on the AM5 memory controller than two, so the system may work with two sticks or at a lower speed even if it cannot train at DDR5-5200.
That makes sense. I had not realized how much harder four modules could be on AM5, so I’ll test each one separately rather than treating the kit as a single unit.
A failed memory module can cause repeated restarts even when the computer was previously stable. Testing every stick by itself in A2 is the quickest way to separate a bad DIMM from a board or CPU problem.