Listen to this guy. Try overvolting your ram a tad. This isn't anything new. It happens when you overclock the ram too far, but since you're at stock then IMHO its grounds for an RMA.
I did hear that there was an update (driver?)to fix this problem. I believe the common factor was that they are factory overclocked cards.
If u have corruption loading and these kinds of artifacts I'd eat my hat if it wasn't vRAM being responsible.
With regards to overvolting your vRAM, I'm not sure there is a separate setting in msi afterburner, its probably tied to the core voltage in that case.
Alternative to overvolting (underclocking ram):
http://forums.overclockers.co.uk/showpost.php?p=26127270&postcount=7