This issue might stem from a defective MoBo.
This issue might stem from a defective MoBo.
It's important to verify if your motherboard supports the newest BIOS version. Correct sensor readings may be resolved through software updates if they stem from bugs. Also, see if you can adjust the 3.3V rail voltage in your BIOS overclocking settings—this is unlikely but free to test. Use Hardware Info to confirm the 3.3V rail isn't undervolted. If needed, proceed with a return of merchandise (RMA). Sometimes that's all you can do.
Last night I changed the CMOS battery. The BIOS reset was successful with no effect. Memory updates also completed without issues. I tested various memory sticks, including a 32GB g-Skill module (2x16GB). After unplugging all memory, the voltage stabilized between 3.1V and 3.2V, allowing file transfers between the two SSDs again. There was a minor power dip to 3.05V, but it resolved. I plan to let it run for a few days and try playing games and editing videos to see how it performs.
I took the issue to a repair shop, and they identified the problem after roughly one test. A faulty cable extender was the culprit. Once it was replaced, the PC showed a much more stable 3.3V output. Thanks to everyone who helped figure this out!