I helped my son build his first PC using a mix of new and secondhand parts, but it has become unreliable during startup. The system initially showed solid red CPU and orange DRAM lights on the motherboard. After troubleshooting, it eventually booted and ran games normally for an evening, but the next morning it returned to the same error and now often cannot even enter the BIOS.
The system uses an MSI B650M Gaming Plus WiFi motherboard with a Ryzen 5 7600X, a used Nvidia RTX 3070, 32GB of Kingston Fury DDR5 in a 2×16GB kit, and a new Corsair CX750 750W power supply. The BIOS has been updated to version 7E24v1E2, and the RAM is currently running at its default 4800MHz speed.
I have tried clearing CMOS, testing each RAM stick individually in A2, removing the GPU and SSD, reseating the CPU, checking the socket for bent pins or thermal paste, and verifying the main power connections. The CPU and DRAM LEDs remain solid, even after leaving the computer powered on for up to 30 minutes. What else should I check, and how can I determine whether the problem is the RAM, motherboard, CPU, or power supply?
3 Answers
Since the machine worked and then became inconsistent, test outside the case to rule out a short or mounting issue. Remove the motherboard from the case and place it on its box, then connect only the CPU, cooler, one RAM stick, PSU, and a monitor. Start it by briefly bridging the power-switch pins with a screwdriver.
If it still shows the same solid CPU and DRAM indicators with each RAM stick tested separately, the next useful step is swapping in known-good DDR5 memory. If different memory makes no difference, the motherboard or CPU becomes much more likely than the SSD or graphics card.
Because it successfully ran games once, the CPU and board are not automatically proven faulty. Start with a completely minimal setup: motherboard outside the case if possible, CPU and cooler installed, one RAM stick in A2, the 24-pin cable and CPU EPS cable connected, and the monitor plugged into the motherboard video output. The 7600X has integrated graphics, so the dedicated GPU and SSD can stay disconnected.
Clear CMOS again, make sure the cooler is not excessively tightened, and confirm that the RAM is fully seated with the locking tabs engaged. AM5 memory training can take several minutes, but a solid pair of CPU and DRAM lights after half an hour suggests something beyond normal training. Try both sticks individually, inspect the socket under strong light, and verify the exact memory kit is supported by the board.
Double-check the CPU power connection rather than only the large motherboard connector. The 24-pin ATX cable and the 8-pin CPU/EPS cable both need to be firmly connected, and the cable must be the correct CPU cable from the power supply—not a PCIe cable. If you have access to another known-good PSU, testing with it would help rule out an intermittent power problem.
I’ve already tried both modules separately in A2, cleared CMOS using the JBAT pins, and left it running for around 30 minutes. The LEDs stay solid the entire time. The CPU socket looks normal to me, and the RAM is at the default 4800MHz setting.