In an embodiment, a model may be created using a register-transfer level (RTL) representation (or other cycle-accurate representation) of the controller and the circuitry in the communication fabric to the controller. The request sources may be replaced by transactors, which may generate transactions to test the performance of the fabric and controller. Accordingly, only the designs of the controller and the fabric circuitry may be needed to model performance in this embodiment. In an embodiment, at least some of the transactors may be behavioral transactors that attempt to mimic the operation of corresponding request sources. Other transactors may be statistical distributions, in some embodiments. In an embodiment, the transactors may include a transaction generator (e.g. behavioral or statistical) and a protocol translator configured to convert generated transactions to the communication protocol in use at the point that the transactor is connected to the fabric.