A few days ago I updated the BIOS on my PC, and since then it has needed two power-on attempts before reaching Windows. From a cold start, it powers on and posts for about 5–10 seconds, then shuts down completely. After waiting another 3–5 seconds, it starts again and boots into Windows normally. This does not happen when restarting Windows, and the system is stable once it is running. The issue also disappears if I leave the power strip switched on and only shut down the PC.
The problem began immediately after the BIOS update. I use EXPO 1 with 64 GB of DDR5-6000 memory, and I understand that some AM5 systems perform memory training during cold boots. However, the double boot happens on every cold start now, whereas it never happened before the update. There are no relevant errors in Windows Event Viewer.
The startup sequence is:
1. Switch on the power strip; the motherboard standby light turns on.
2. Press the PC power button; the AIO, fans, and RGB lighting start.
3. After 5–10 seconds, the system shuts down while the motherboard standby light remains on.
4. After another 3–5 seconds, it powers on again, completes POST, and loads Windows normally.
System specifications:
- Windows 11 Pro 25H2
- AMD Ryzen 9 7950X3D
- Sapphire RX 7900 XTX Nitro+
- ASUS Crosshair X670E Hero, BIOS 3902
- 64 GB Corsair Dominator Titanium RGB DDR5-6000 with EXPO 1
- Samsung 990 Pro 2 TB and 870 EVO 4 TB
- Corsair iCUE Link H170i LCD
- Seasonic Prime TX 1000W
The BIOS was reset to defaults after the update. The only settings I changed afterward were enabling EXPO 1, selecting Windows UEFI mode, and leaving Secure Boot on Standard. Is this expected AM5 memory-training behavior, or could the BIOS update have exposed a hardware or configuration problem?
3 Answers
The fact that it only happens after the PC and power strip have both been off is another clue. A restart, or shutting down while the power strip remains on, does not fully reset the memory-training state. That behavior is consistent with cold-boot initialization on AM5, although it is still worth testing EXPO off and checking whether a newer BIOS improves it.
The simplest diagnostic is to turn EXPO off temporarily and leave the memory at its default settings. If the double boot disappears, the issue is related to memory training or the current EXPO timings rather than Windows. Since the computer is stable after the second start, the memory profile may simply need to be retrained or adjusted by the newer BIOS.
The pattern strongly points to DDR5 memory training. AM5 systems can retrain memory after a BIOS change, especially with 64 GB and EXPO enabled. A cold boot forces the memory to initialize from scratch, while a restart may skip that process because the memory state is still retained. The BIOS update likely cleared the previously trained values, which is why the behavior started afterward.
On the Crosshair X670E Hero, try enabling Memory Context Restore so the board can reuse successful training results. You can also test with Power Down Enable disabled if Memory Context Restore by itself causes instability. This is usually an annoying firmware or memory-training behavior rather than a sign that the CPU, GPU, or power supply is failing.
That makes sense, although it happens on every cold boot rather than only once after the BIOS update. I’ll test Memory Context Restore and compare the behavior with EXPO disabled.
I haven’t tried disabling EXPO yet, but I’ll use that as a test. It should help confirm whether the BIOS update and memory profile are the cause.