Only gather information about current system, but places no value judgments on the findings.
Validate: to determine application’s bug under high load condition ( stability) Stress test help to identify the weak points of the applications, what kinds of failure are most valuable to plan for.
Verify: check that your application can meet performance objective A load test enable u to measure response time, throughput rate, … Help to determine how many users applications can handle before it is compromised.