no real reason to overclock now that CPU's support 3200mhz RAM and you can guy 3200mhz ECC.Yeah I am not sure what what it would take to simulate. You need to get the timings such that writes work perfectly fine and just a few reads will fail. Too many, or to big of an error (Unrecoverable) and the system will crash.
I have never overclocked ECC ram, as that is kinda counter productive, so I am not sure what it would take.
Assuming it is even working at all. I would expect them to show up in the IPMI side over the OS if it is a drive issue, and if that isn't working it likely isn't catching them or your just extremely lucky writing 10=reading 10 until you hit a speed then nothing works.
also, I wonder if Windows 10 for WorkStations or Enterprise would report ECC function correctly?