Which tool is ideally the only source of execution burden experienced by the system under test?

What test script operating conditions are risks to a performance test's validity?
i. Record insertions align with transaction objective
ii. Component failure within the system under test
iii. Load generator produces low load level
iv. Database log remains synchronized with load generators time source
v. Virtual users authenticate with distinct IDs

Which tool is best suited for determining resource utilization of a system component under test?