Problem with slow network

hi all, recently migrated CMS version 7.1 to 7.5, turn off the option to legacy agent and Inventory policies, agents are in 7.1, the problem is that many agents make requests to the server 7.5 and the network becomes too slow, and I can resolve this problem?, which is what caused this affectation to the network?, as I can limit the bandwidth?, thank you for your answers