The Dane starred in Australia, finishing third on the road before being promoted by Daniel Ricciardo's exclusion for exceeding the fuel-flow rate, but has failed to score a point since.
"Obviously, he is a young rookie driver and it reminds me, in my experience [as team principal at Renault/Lotus] of [Romain] Grosjean and [Vitaly] Petrov," said Boullier when asked by AUTOSPORT about Magnussen's recent results.
"They went through the same processes, it's part of the learning curve, unfortunately.
"They are inexperienced and need to be able to understand the car.
"It's not helped by the fact that he has a car that is not so easy to drive today."
Magnussen admitted before the Chinese GP that he found it challenging to race down the order in F1.
He had a clean race in China, but like Jenson Button he struggled because of the McLaren's lack of downforce, finishing only nine seconds behind his team-mate.
"Just lack of downforce really, it's a shame because we just don't have enough," said Magnussen.
"I think that's the only problem we have with the car. The way the car is run and the way it feels is good, it just lacks overall grip."
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