Much slower replication on Innodb compared to myisam
Make sure your disks are fast enough to catch up master.

The problem is that innodb is a transactional storage engine. It writes first into undo log and only then modified data to the tablespaces. The second issue is that mysql replication by default is single threaded. It means that transactions applied on the master in parallel will be in the binlog in sequential order, and all of them will be applied sequentially on the replica. You can try parallel replication toprocess binlog events in parallel.