From the time computing technology came into existence, it has been quite difficult for people to differentiate between stress testing and load testing. The reason being both of them share common features and the distinction is only due to the difference in the intensity of server resources.
Both these terminologies are very common in computing in businesses like the banking or finance industry where several users use the same system at a particular time to obtain information
In general load testing is to evaluate the common servitude of the system towards routine events. In layman terms, a system is subject to a fixed number of users at a time and it has been functional over a particular period.
Therefore load testing answers our queries about the system's efficiency, the problems that could arise if the load was suddenly increased and the remedies that could be implied to improve the system.
Stress testing, on the other hand, means a situation where a system has been subjected to extreme conditions. This could either mean that the system has been worked over the normal working hours or as in the banking industry being used by too many users at the same given time. Stress testing would present obstacles like system jamming or running slow than normal.
The main issue with these two terminologies has been the idea of when precisely load testing changes to stress testing. The main issue is that there is no metric which marks or suggests when the load subjected to a system transmutes into stress and begins jamming it.
The subtlety between the two, therefore, is the fact that stress testing is the subjection of stress to the system by raising contributing factors like the number of users which is a major contributing factor for testing if the system meets the desired standards or not. On the other hand, load testing is mere testing at a given time how much a system could work under a normal situation and the possible obstacles that could arise and how it could be resolved. To conclude, stress testing is load testing by a double or a treble scale.