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.
hmm i messed up then. have a powercolor 470 4 gb red devil single fan 470 with samsung mem. copied the 1500 strap up (oops) and run it at 1300/1850 for 26.5 mhs. mining eth.
gonna redo it with the 1750 strap and run the mem up to 2000 or so and see what happens.
Samsung is a very good and optimised memory, indeed they have lower timings.
That's the reason why 1500 Straps are too tight and you need to use 1750. Someone uses 16** timings with good results either.