is there a way to get the memory tester he mentioned? Is it open source? Once Ram goes bad is there a way or recovering it or is it toasted forever?
Errors may be caused by bad seating/contact in the slots or failing memory controllers (generally on the CPU nowadays) but if you have bad sticks they're generally done for.
You can map known-bad memory regions to avoid using them.
https://www.memtest86.com/blacklist-ram-badram-badmemorylist...