For high performance computing design, designer always wants to know the maximum frequency and the minimum working voltage. However, due to the voltage limitation of foundry-provided timing lib, it is impossible to cover the performance of design under different voltages by using STA. This paper introduces a performance prediction solution with the aid of ICE-XTime. It can simulate the critical paths based on controlled voltage sweep. After simulation, the timing data will be collected to help designer predict the performance changes at different voltages.