A method, system, and apparatus for testing a scalable computer system is provided. In an illustrative implementation, a system for testing a scalable computer system includes configuring a single cell on a partitionable system to create an isolated test channel. A test packet is generated and provided to the test channel. The test channel inserts the test packet into the scalable computer system via a communications link, and a response to the insertion of the test packet is monitored to determine system performance.