Yes, Samsung are currently nowhere near Hynix on MHz/volt: the best kits can barely do 1500MHz 15-16-16 fully stable at 1.35V or less, whereas 98%+ of Hynix can do 1500 15-15-15 1.35 easily.
Some of Samsung is so bad that it can't even do 1200MHz 14-14-14 at 1.20V.