Final answer:
High-speed networking between nodes and parallel reading of large data files are the two factors that significantly increase performance in a Hadoop cluster.
Step-by-step explanation:
The two factors in a Hadoop cluster that significantly increase performance are high-speed networking between nodes and parallel reading of large data files. High-speed networking allows for efficient communication and data transfer between the nodes, while parallel reading of large data files allows for faster processing and analysis of the data. These factors contribute to better overall performance and scalability of the Hadoop cluster.