Performance testing - It is the testing process to test the
speed and efficiency of an application.

Load Testing - It is a process to test the application with
the maximum number of user it can support. for example 
How many users can use the system simultaneously before it
slows down or fails.

Stress Testing - It test the application with more than
maximum number of users application can support

Performance tests can be broadly classified in to
Load tests
Stress tests
Endurance tests
Spike tests
Capacity testing
Load test

Load tests are performance tests which are focused on 
determining or validating performance characteristics of 
the product under test when subjected to workload models 
and load volumes anticipated during production operations. 

What are the benefits?
Helps

Evaluate the adequacy of a load balancer.
Detecting functionality errors under load.
Determine the scalability of the application OR for 
capacity planning purposes as the need may be.
What risks does it address?

How many users can the application handle before “bad 
stuff” happens
How much data can my database/file server handle?
Are the network components adequate?
Stress test
Performance tests focused on determining or validating 
performance characteristics of the product under test when 
subjected to workload models, and load volumes beyond those 
anticipated during production operations.

These tests are all about determining under what conditions 
an application will fail how it will fail and what 
indicators can be monitored to warn of an impending 
failure.

What are the benefits?
Helps

Determining if data can be corrupted by over stressing the 
system
Estimating how far beyond the target load an application 
can go before causing failures and errors in addition to 
slowness
Establishing application monitoring triggers to warn of 
impending failures
Ensuring that security holes are not opened up by stressful 
conditions.
Determining the side effects of common hardware or 
supporting application failures.
What risks does it address?

What happens if we underestimated the peak load?
What kind of failures should we plan for?
What indicators should we be looking for to intervene prior 
to failure?
Endurance test 

A performance test focused on determining or validating 
performance characteristics of the product under test when 
subjected to workload models and load volumes anticipated 
during production operations over an extended period of 
time.

What are the benefits?
Helps

Slow memory leaks
Insufficient file storage capacity
Performance degradation as a result of an increased in 
stored data
Overnight, automatic virus definition updates on a server 
causing performance degradation
What risks does it address?

Will performance be consistent over time?
Are there slow growing problems that we haven’t detected?
Is there external interference that we didn’t account for?
Spike test 

A performance test focused on determining or validating 
performance characteristics of the product under test when 
subjected to workload models and load volumes that 
repeatedly increase beyond anticipated production 
operations for short periods of time.

What are the benefits?
Helps Identify

Memory leaks
Disk I/O (thrashing)
Slow return to steady – state
What risks does it address?

What happens if we underestimated the peak load?
What kind of failures should we plan for?
What indicators should we be looking for to intervene prior 
to failure?
Capacity testing

Capacity testing is related to stress testing .It 
determines your server's ultimate failure point. You 
perform capacity testing in conjunction with capacity 
planning. 

You use capacity planning to plan for future growth, such 
as an increased user base or increased volume of data. For 
example, to accommodate future loads you need to know how 
many additional resources (such as CPU, RAM, disk space, or 
network bandwidth) are necessary to support future usage 
levels. 

Capacity testing helps you identify a scaling strategy to 
determine whether you should scale up or scale out.

What are the benefits?
Helps Identify

Provide actual data to the capacity planners to validate or 
enhance their models and/or predictions.
Conduct various tests to compare capacity planning models 
and/or predictions.
Determine current usage and capacity of existing system to 
aid in capacity planning.
Provide usage and capacity trends of existing system to aid 
in capacity planning.
What risks does it address?

Validate that capacity planning models represent reality.
Ensure capacity planning remains in sync with actual system 
usage and growth patterns.