PC boot loops occurring during or after POST, it's unclear which part is responsible.
PC boot loops occurring during or after POST, it's unclear which part is responsible.
This machine functioned properly the previous night, yet now it won't power up. Here are the details:
Processor: Intel Core i7 12700K
Motherboard: MSI PRO B660M-A WiFi DDR4
RAM: 2x HyperX DDR4 8GB at 2666 MHz (no RGB)
GPU: MSI RTX 3060 GAMING X 12G
Power Supply: Deepcool DA500 (500W, 80Plus bronze, older model) – label shows it was once an XPG Pylon 750W, which failed about a month after purchase
What I've tried and observed:
- Debug LEDs illuminate in sequence: CPU → RAM → GPU
- Reboots occur; CPU lights up again after power loss
- No BIOS changes made; CMOS cleared didn’t help
- Power button tested – not the issue
- No signs of failure in power circuitry or button
Tried removing everything, booting with minimal components (CPU, cooler, GPU, one RAM stick) – still no start.
Swapped CPU, GPU, and RAM; changed RAM slots; used alternate PCIe slot for GPU – all failed.
Using a different motherboard and CPU (MSI B365M + i5 9400F) worked with both GPUs, same PSU and RAM.
Possible causes:
- The PSU might be insufficient or degraded
- There could be a fault between the CPU and motherboard
- The system is experiencing power delivery issues
Given components are recent and have operated normally before, the PSU seems likely culprit. It may have become underpowered over time, though that’s unusual. I recommend checking the PSU’s capacity and condition before proceeding with replacements.
I'm not sure if the 500W will fit properly. Could you share your full system details—storage, case, any fans or coolers? That way I can estimate your total power usage.
It shouldn't be the PSU because it would either function properly or not at all. The real concern arises when the system is operational but the PSU fans fail to run, leading to overheating and a shutdown. Unless that's the case, the PSU shouldn't be the issue since it does power on. Overheating usually happens only under heavy load where cooling fails, not just during normal operation. You also mentioned success on another system, suggesting the problem might lie elsewhere. You considered swapping RAM sticks, but personally suspect a motherboard fault. Check CPU temperature while powered on—if it stays cool or shows no cycling, the CPU may be the culprit. Try replacing the CMOS battery on another board to rule that out. If the issue persists after replacement, consider borrowing another motherboard and testing. Even if under warranty, getting a CPU or motherboard swap can help isolate the problem.
I’m considering more closely due to the bootloop—it doesn’t start pulling 500W right away because it’s near the limit. Once the fans spin up, storage, GPU, and RAM kick in, it surpasses the PSU’s wattage and shuts down. But since it’s still in boot, it tries again, treating it as a failed boot and restarting the loop. That said, I might be mistaken; it could just be a theory.
Three case fans featuring ARGB lighting (InWin Sirius Loop) are being discussed. The cooler is the Peerless Assassin 120, which includes two additional ARGB fans. The storage setup consists of one NVMe (PCIe Gen 3), one SATA SSD, and one HDD (7200RPM). The case model is Fantech Pulse CG71, displaying only RGB on the front and providing front I/O. There are several USB devices present such as a gaming mouse and keyboard, a USB 2.0 hub, a wireless headset dongle, occasionally a budget USB capture card, and an Arduino Uno R3. In this configuration, the PSU fan activates properly. Attempts to install RAM were unsuccessful on each slot, especially when a GPU is present. The CPU and cooler heat up noticeably. I haven’t left the system long enough to force a reboot, but I’ll check later. The CMOS can be tested, though it would likely trigger an error if dead. I plan to replace the PSU for better reliability and efficiency.