To "realize" is to understand. Where previously you didn't get something, now it is clear.
To "realize" is also to make real. Where previously it only existed in one's imagination, it now exists in the physical world.
The first definition is the common one, but the second one is used just enough to avoid being archaic, but is so rare as to almost always be momentarily confounding - as though your brain has to back up and then remember that "realize" has the uncommon alternative definition.
This is especially true when there is a similarity in sentences. For example, "I realized my desire" could perfectly use both definitions. "I realized my efforts" leans more on the archaic definition, but could very easily be the common one if there is more after that phrase. "I realized where my computer came from" is guaranteed to be the common definition unless they managed to create China.
I don't know if the older version of "realize" will be relegated to archaic definitions; it's not my choice alone. But for as long as I can use it and be understood, I shall.