Difference between system testing and system integration testing?

System Testing: It is used to check if the software system is made according to the user requirements, if it is acting according to it. It should meet both the functional and Non-functional Requirements of the system. Performed by Testers. It is a black box testing technique.  It is a high level testing.

System Integration Testing: It is used to check if the modules developed when combined together is giving the expected result. Only Functional Requirements is covered. Performed both by Testers and Developers. It is both black box and white box testing approach. It is a low level testing.