The goal of this study is reducing the time complexity of complex processes by using parallel programming on multi core PCs which is widely used in our daily computers. In this regard, same level as a result of the acceptance can be obtained in a shorter operating time by parallel implementation of an algorithm. Because of the increasing number of cores in processors with each passing day, we made sure that the application is scalable. This study show, if we implement the same problem parallel, the significant increase in performance occurs by increasing the number of cores. We implemented genetic algorithm to optimize Rastrigin function using Intel TBB. Our tests are made in two different computers. First computer contains the processors of Intel i3 M370@2.4 GHZ which has two core and each core has HT (hyper threading ) running on Microsoft Windows Seven operating system. Second computer contains the processors of Intel i5 520M@2.4 GHZ, which also has two cores and each core has HT as previous processor, running on Apple Mac OSX Lion operating system. In this study, not only the comparison of the serial and parallel versions of algorithm in the same platform is observed but also the differences between two different platforms are observed due to the operating time.