The performance of all-optical logic XOR gate for phase-shift keying modulated data signals has been numerically simulated. This Boolean operation is realized by using a Mach-Zehnder interferometer utilizing semiconductor optical amplifier. The effect of the parameters that are critical for the performance of the scheme on the quality factor is taken into account and investigated. The analysis shows that if these parameters are optimized then the all-optical XOR gate scheme can operate with high performance at data speed of 100 Gb/s for the first time.