Obviously you want to focus your testing on whatever subsystem you're trying to OC. I was just giving generic advice on overclocking. There is pretty broad consensus that Prime95 is a good stability test for CPUs.
Someone also suggested Intel Burn Test as a test that might catch some instabilities that Prime95 misses in a reply and then deleted it for some reason (why?).
In particular though, it's not just the memory subsystem you're overclocking here, you're really overclocking the interconnect as well. It will have its own "silicon lottery" and a particular point of instability, in addition to your individual memory kit's own stability characteristics. There are a lot of moving parts here.
I do wonder how much of this is getting the memory controller stable versus getting the interconnect stable. It seems possible they may have knobs they can twiddle on the interconnect as well.
[Serious question here:] I wonder if Prime95 or burn-test type tools would stress the interconnect with enough cross-core communication to be worth running.
Is it because the question is not whether or not a particular bit of RAM is damaged and rather whether or not the overclock to the communications bus between CPU and RAM is affected?