LTE wireless mobile broadband networks, in particularly those based on 3GPP Release 8 (Rel. 8) specification, have already made strong inroads into the commercial arena worldwide. In Malaysia, 8 companies have been allocated spectrum in 2.6GHz Band (LTE band class 7). This paper aims to provide some high level insights on the throughput performance of these spectrums. Although a lot of studies have been undertaken with regards to LTE network performances, various degrees of discrepancy still exist in particularly concerning network layer (IP) throughput. A wide array of factors may contribute to these differences, which include differences in methodology adopted, levels of abstraction (or details) used in the simulation model, environment and/or usage scenarios and so on. Using OPNET's latest LTE library, we study the effects of duplexing scheme (FDD vs. TDD), MCS, channel bandwidth, bearer's type (GBR or non-GBR) for the allocated spectrums. The impact of multiple users' access on the throughput performance is also analyzed. This work enables us to compare and contrast our findings with the existing studies while providing more accurate views on how the main system level configurations may impact the network layer throughput performance of the emerging LTE networks in Malaysia.