I have 24 of the MSI 470s and they are my favorites, I actually prefer them over the Sapphire 480/8GB variants which I have as well.

My latest batch of MSI 470s (4GB) have Samsung memory.  You didn't take the 1500 strap and copy it up and expect it to clock at 2k on Samsung memory did you?

On my MSI 470s with Samsung VRAM I copied the 1750 strap to the 2000 range and I am running them at 1150/2100 and I am getting 29.3Mh/s out of them rock stable.