NSOperationQueue maxConcurrentOperationCount –1 and undocumented system throttling boundary
NSOperationQueue is configured with maxConcurrentOperationCount set to –1, which is documented as unlimited. In practice the system caps the number of concurrent threads for a queue based on CPU and memory resources. The throttling policy and thresholds are not documented, and the queue’s internal throttling state is not exposed through a public API. Develop