Id Tech 7's main selling point has been that it has "10 times the geometric detail" of the predecessor.
I don't know about 3d engines, but arbitrarily increasing the number of poligons is something any engine can do; if they refer to speed instead, I'm very skeptical that it can render 10 times as much polygons in the same amount of time.
Does anybody have a wild guess about what this could mean? Or is it marketing garbage?