[Context] A variety of testing tools have been developed to support and automate software performance testing activities. These tools may use different techniques, such as Model-Based Testing (MBT) or Capture and Replay (CR). [Goal] For software companies, it is important to evaluate such tools w.r.t. the effort required for creating test artifacts using them; despite its importance, there are few empirical studies comparing performance testing tools, specially tools developed with different approaches. [Method] We are conducting experimental studies to provide evidence about the required effort to use CR-based tools and MBT tools. In this paper, we present our first results, evaluating the effort (time spent) when using LoadRunner and Visual Studio CR-based tools, and the PLeTsPerf MBT tool to create performance test scripts and scenarios to test Web applications, in the context of a collaboration project between Software Engineering Research Center at PUCRS and a technological laboratory of a global IT company. [Results] Our results indicate that, for simple testing tasks, the effort of using a CR-based tool was lower than using an MBT tool, but as the testing complexity increases tasks, the advantage of using MBT grows significantly. [Conclusions] To conclude, we discuss the lessons we learned from the design, operation, and analysis of our empirical experiment.