I tried overclocking my 128GB of ECC UDIMM RAM, but that didn't lead anywhere. Not sure what was causing issues, and I don't have the equipment to even attempt to look at the signals. I'm thinking either low headroom on the RAM, or the memory subsystem just not being able to handle full banks + ECC + fast clocks.
Not too interested in trying out other RAM considering the price, but maybe once there's a new TR socket.