I bought a second-hand B450 Steel Legend motherboard. Its RGB lighting comes on immediately, but it takes roughly 10–20 minutes before the system displays anything or responds to the keyboard. I tested a different graphics card, power supply, and RAM, with the same result. I also tested both my Ryzen 5 3500 and Ryzen 7 2700 in another motherboard, where they worked normally. The motherboard seems like the most likely problem, but I'm not sure what to try next. I also attempted a BIOS update, but the board does not detect the BIOS file on my USB drive.
3 Answers
A dead CMOS battery can cause the BIOS to lose its settings and repeat memory training on every boot, but you’ve already replaced the battery. At this point, clear the CMOS properly, test with one RAM stick, and confirm the BIOS file and USB drive meet the board’s update requirements. If the delay remains, the second-hand motherboard may have a hardware fault.
This could be extremely prolonged memory training. The board may be repeatedly trying to optimize the RAM before it reaches POST, although 10–20 minutes is far beyond what would normally be expected. A failing board or an issue saving BIOS settings would be more likely if this happens on every startup.
I considered memory training too, but it shouldn’t take anywhere near that long.
Since the CPU, graphics card, memory, and power supply have all been tested or replaced, the motherboard is the strongest suspect. CPUs fail much less often than motherboards, especially when both processors work correctly in another system.
I tested both a Ryzen 5 3500 and a Ryzen 7 2700 in another motherboard, and both worked there.
The CMOS battery has already been replaced, so I’m increasingly convinced the motherboard itself is defective.