A circuit board includes a substrate and electrical contacts to mate with a slot connector. The contacts include a first set of contacts that are associated with the communication of power and second set of contacts that are associated with the communication of signals and are not used to communicate power. Adjacent contacts of the first set have a first spacing, and adjacent contacts of the second set have a second spacing different from the first spacing. The circuit board has a retention profile to engage a retention mechanism of the slot connector. A housing of the slot connector may be made from a material that has a thermal conductivity of at least 0.27 W/m·K, and the slot connector housing may include fins that are formed on the slot connector to conduct heat away from circuitry of the circuit board.