[mnw21cam]

Two things. Firstly, I don't think any conclusions can be made about whether dd or dd-rescue is more susceptible to bit flips. It could be that both allocated a buffer, and dd-rescue just happened to be handed the area of memory with the fault in it, which it reused multiple times, where when dd was run that area of memory was used by something else. Memory mapping and usage in a real operating system is highly non-deterministic due to the sheer amount of things that affect it.

Secondly, once a good list of known faulty memory addresses had been created by memtest, one can tell the operating system not to use them. Then you can keep using your old hardware without the reliability problems. Although, it is possible that further areas of memory will subsequently fail, and without ECC, you'll still be vulnerable to random (cosmic ray-induced) bit flips.