Actually, it is quite the opposite, Anakin is ruled by passion, Vader is cold and calculated.
Anakin is younger, without much experience, born as slave, separated from his mother, never had a father. He acts in a moment, without thinking. When in deep emotional state, he is capable to do very un-Jedi things like killing Sand People and force choking Poggle the Lesser. And when he finally snaps and goes to Dark Side, he slaughters younglings and his former Jedi friends. But he doesn't finish his transformation in the Darth Vader until he gets crippled and confined in life supporting suit.
And then we have Vader with his constant, cold, calculated and deliberate hate. Pain is a constant for Vader. It is his life, as is constant hate - hate for himself, Palpatine, Padme (yes, even her !), other Jedi (dead and living), whole Imperial charade and Rebels. They all remind him what pitiful wretch he is now. But he has no use for quick anger - he is much smarter and in his suit much slower and restricted.
He now knows that he depends on others - from Palpatine to sergeant loading his meditation chamber into ship (novel "Tarkin"). Yes, he hates them, but he cannot go against them all. So he occasionally chokes, and sometimes kills under-performing Imperial or snotty Rebel. But he has to plan ahead. Every move is pain, and every move is calculated. He plans and schemes, sets ambushes for Rebels, lets them think they have won only to achieve his goal in the end. So, he is not a sword, but finely tuned swordsman very few could outsmart.