A compression backup is smaller than uncompressed backup. The backup speed significantly increases because it needs less disk space and I/O operations. The CPU usage is increased and the increased and the additional CPU that is consumed by the process of compression would impact the operations that are running concurrently.

The following processes can be isolated for obtaining a good picture

- Physical disk counters

- Device throughput bytes / second counter of SQL Server Backup Device object

- Backup/Restore throughput / second counter of SQL Server Databases object.