Mobile Ad hoc Network (MANET) contains mobile nodes which exchange information dynamically over wireless links. Routing Protocols are the most vital element of MANET, which are needed to handle dynamic communication and also find route. Performance of routing protocols is an important issue. In MANET, due to mobility of nodes, the wireless links are highly error prone and can go down frequently, interference and less infrastructure. In this research, performance of Optimized Link State Routing (OLSR), Temporary Ordered Routing Algorithm (TORA) and Geographic Routing Protocol (GRP) routing protocols are evaluated in mobile Ad hoc network by using simulator against various quantitative metrics like Network Load, Throughput, Retransmission Attempts and Media Access Delay by varying physical characteristics, number of nodes, nodes speed and pause time. Various simulation scenarios are investigated by varying matrices. A comparative performance analysis of aforesaid protocols is carried out in this research. In the last, conclusion is presented which demonstrates that performance of routing protocols differs by varying matrices.