The phrase "actually the most efficient" is correct and usable in written English.
You can use it when you want to emphasize that something is indeed the most efficient option among alternatives.
Example: "After reviewing all the methods, I found that this approach is actually the most efficient for our needs."
Alternatives: "truly the most effective" or "genuinely the best option".
A reminder that not throwing stuff away is actually the most efficient way to cut waste.
Lehmann said that the startup found bike deliveries were actually the most efficient way of getting around New York City.
Despite out agreement on this matter, I would like to differ and point out that consumerism is actually the most efficient way of reducing poverty, as discussed by Bill Gates in his article Why Inequality Matters.
The largest inland delta in the world, horses are actually one of the most efficient ways to travel around this network of hippo-created water channels and islands.
So bots shouldn't be limited to their "chatbot" ancestors, and the most efficient ones are actually able to blend all of these capabilities.
At the other end of the spectrum, at the very other end, is letting people keep more of their money, which — while it can contribute to the deficit in a large fashion — is the most efficient way to actually allocate resources … I'm really not interested in how tax reform handles the deficit.
Actually, it seems to be clear that the most efficient improvement would be to consider not a window but a priority queue.
It is only valuable when it can be the most efficient channel for customers to actually engage via a question and answer kind of way.
The most efficient business practices happen when we actually let go.
The most efficient measure for human protection is actually the vaccination of dogs.
To the contrary, discretization actually complicates the optimization problem by making it difficult to apply the most efficient and powerful search techniques.
