Link Aggregation increases bandwidth and throughput by aggregating multiple network interfaces and provides traffic failover to maintain the network connection in case the connection is down. The total network bandwidth will only increase if there are multiple clients. Each client will be answered by one of the bonding interfaces. Once an interface is assigned, all connections from this client will be answered by the same interface.

To test the performance after setting up Link Aggregation, upload or download a big file (e.g. a 4GB movie) from two or more computers to your Synology NAS. You can then monitor the network bandwidth in Resource Monitor > Performance on DSM and compare the results when you upload or download the file with a single client.