Same thing. Samsung and SkHynix make all the ic's for the gskill Trident-Z series, the Royals are supposedly better binned, but have standard CL timings. This allows for better OC above and beyond the jedec settings and the best chance of stability/compatability at rated speeds. That and the Royals have a limited edition heatsink/rgb.
For all intents and purposes, the Royals are the Dominators of the gskill brand.
As far as speed compatability goes, the Royals shouldn't have any issues, speeds are set by the cpu/memory controller, which for 2ndGen Ryzen is 3200MHz on the jedec tables. The RGB is a different story, it's not a standard controller so may or may not be compatible. As far as I know, Asus Aura Sync was compatible, but not...