1. One or more computer-readable storage media encoding instructions that when executed instruct a processor to perform a method of simulating a computer system performance scenario, the method comprising: generating one or more sample transactions for each of a transaction type; calculating an action latency representing a time over which a device processes each sample transaction; calculating an instantaneous device utilization representing a level of device utilization when processing each sample transaction; calculating an overall device utilization representing a level at which the device is utilized in a computer system performance scenario, the overall device utilization being calculated by multiplying the action latency, the instantaneous device utilization, and a frequency of each transaction type; modifying the performance scenario based at least in part on the overall device utilization; simulating the computer system performance scenario; and providing results of the simulation to a user.