Checked the logs in Windows, you're right! A corrected hardware error has occurred from PCI Express Root Port. I reseated the drive with no change.
I should mention that this laptop has always had issues with what I assumed to be thermal throttling. It would play games fine for 10-15 minutes before becoming a slideshow. I eventually stopped trying.
I have set that option and I am currently downloading a GPU benchmark. Is that an appropriate test? What should I be looking for in dmesg?