A disk drive testing system cooling circuit includes a plurality of test racks. Each of the test racks include a test slot compartment and a test electronics compartment. Each of the test slot compartments includes multiple test slots, and one or more cooling conduits configured to convey a cooling liquid toward the test slots. Each of the test electronics compartments includes test electronics configured to communicate with the test slots for executing a test algorithm, and a heat exchanger in fluid communication with the one or more cooling conduits. The heat exchanger is configured to cool an air flow directed toward the test electronics.