The differences were far greater. For starters, they had different beliefs, and not only religious beliefs but about life in general. They also used different weaponry and went through different types of training. Knights would also have land and control it while pledging allegiance to the King, while Samurai were not as powerful as nights were and were more just soldiers. They also came from different social backgrounds. If a knight's king would die they would just pledge their allegiance to the new king, while Samurai's lord's death would mean more or less the end of a samurai's job.
