I added another 16 GB RAM kit to my PC, bringing the total to 32 GB. The two kits are mismatched: one is rated for 3200 MHz and the other for 3000 MHz. They worked together for a couple of weeks, but after setting the memory speed to 3000 MHz and rebooting, the system triggered BitLocker recovery and now repeatedly returns to the BIOS instead of starting Windows.
I recovered BitLocker and tried setting the RAM to 2400 MHz, 2800 MHz, and Auto. I also removed the newer sticks and tested with only the original two, checked the BIOS settings, and toggled CSM. With CSM enabled, I can choose between Windows Boot Manager and an AHCI entry for the drive; with it disabled, only Windows Boot Manager appears. I would prefer not to wipe and reinstall Windows unless necessary.
The system uses an ASRock B450 Pro4 with BIOS P5.00 and a Ryzen 7 5800XT. Another strange symptom is that the BIOS clock sometimes fails to keep time. I also tried removing the CMOS battery, but that did not resolve the boot loop. A Windows reinstall began but stalled around 50%, rebooted, and returned to the BIOS instead of completing.
3 Answers
The clock losing time is a major clue. Replace the CMOS/CR2032 battery, then load the BIOS defaults and manually confirm the correct boot mode and boot device. A dead battery can cause firmware settings to reset, including TPM, Secure Boot, CSM, and storage settings. After resetting everything, select the existing Windows Boot Manager entry rather than the raw drive or AHCI entry.
Mixed memory kits can be unstable even when both kits work at their advertised speeds. For troubleshooting, leave only the original matched pair installed, clear CMOS, and run them at the motherboard’s default settings. If the machine still cannot boot with the original RAM, the problem is probably the changed firmware configuration or storage boot mode rather than the additional memory itself.
Since the original sticks worked before the speed change, it makes sense to test with only that pair and avoid enabling XMP or manually setting the frequency until Windows boots normally.
A reinstall probably will not fix this if the computer keeps entering firmware setup. First verify that the Windows drive is detected and that Windows Boot Manager is the first boot option. Keep CSM and Secure Boot in the same mode they were using when Windows was installed; switching between UEFI and legacy modes can make an otherwise intact installation appear unbootable. If the installer also reboots into BIOS, check the drive connections and its health from another boot environment.
I removed the battery once, but the system still disabled TPM and continued looping. I’ll try a fresh battery and recheck the boot settings after clearing CMOS properly.