What's causing my computer to crash (ntoskrnl.exe+4f8450)?

ntoskrnl.exe in the bug check stack does not by itself identify the root cause. It is the Windows kernel and appears in almost all crash dumps. The context indicates that repeated blue screens and unexpected restarts on Windows 11 are typically caused by:

• Faulty or incompatible hardware recently added (motherboard/CPU/RAM)
• Device drivers (GPU, chipset, other third‑party drivers)
• Software that corrupts memory or kernel structures

Given the recent platform swap (new CPU, DDR5, motherboard) and that core checks (sfc /scannow, chkdsk, memtest) and driver updates have already been done, the next steps are to systematically isolate hardware/driver causes and ensure the system is stable under Windows 11:

1. Remove or test new hardware
   • Temporarily remove or disconnect any non‑essential new hardware or peripherals added around the same time as the crashes (extra PCIe cards, USB devices, storage).
   • If crashes stop, reintroduce devices one at a time to identify the problematic component.
2. Boot into Safe Mode and observe
   • Start the PC in Safe Mode as described in Start your PC in safe mode in Windows 11 from the troubleshooting article.
   • Use the system for a while in Safe Mode. If crashes do not occur there, this strongly points to a third‑party driver or software (for example GPU utilities, overclocking tools, vendor “optimizer” software) rather than core hardware.
3. Check Device Manager for problematic drivers
   • Right‑click Start → Device Manager.
   • Look for any devices with a yellow exclamation mark.
   • For each such device, choose Update driver. If that does not help, disable or uninstall the device and test stability.
4. Ensure sufficient free disk space
   • Confirm that the system drive (typically C:) has at least 10–15% free space. Low free space can interfere with paging and dump creation and contribute to instability.
5. Keep Windows fully updated
   • Go to Start → Settings → Windows Update → Check for updates and install all available updates. Some kernel and driver‑related fixes are only delivered through cumulative updates.
6. Use crash dumps to narrow the cause
   • Small memory dump files (in %SystemRoot%\Minidump) contain the stop code, parameters, and list of loaded drivers. These can help identify whether a specific third‑party driver is involved, even when ntoskrnl.exe appears in the stack.
   • Ensure a paging file exists on the boot volume (at least 2 MB) so dumps are created reliably.
7. If crashes persist
   • If repeated crashes continue after the above steps, use a recovery option such as System Restore or a repair/reinstall path from Recovery options in Windows 11 to roll back to a known‑good state.
   • For advanced analysis, follow the guidance in the bug check documentation to interpret the stop code shown on the blue screen and correlate it with the loaded module name, then update/remove that module or its associated software.

These steps align with Microsoft’s recommended process for repeated stop code errors and unexpected restarts on Windows 11, where ntoskrnl.exe is often only the last component on the stack rather than the root cause.

References:

• Troubleshooting Windows unexpected restarts and stop code errors
• Bug checks (stop code errors)
• How to read the small memory dump file that is created by Windows if a crash occurs