This paper deals with optimal partitioning of limited testing time in order to achieve maximum total test score. Nonlinear optimization theory was used to analyze this problem. A general case using a generic item response model is first presented. A special case that applies a response time model proposed by Wang and Hanson (2005) is also presented. Theoretical properties of the optimal solution are derived. Their practical implications to optimal test-taking strategies are also discussed. The theoretical properties are in general agreement with the conventional advice to the examinees on pacing strategy.