Handover procedure in LTE/LTE-A has been radically evolved when compared to the previous 3GPP standards. In particular, X2 handover is introduced to allow neighboring eNBs to handle the user mobility without the involvement of the core network. While most of the application could considerably benefit from the X2 handover performance improvement, delay breakdown and impact of parameters from the UE perspective are not well investigated. This paper analyzes the performance of the X2 handover from the UE perspective. Furthermore, the impact of the different parameters on the handover decision algorithm is investigated. Preliminary results, obtained from the OpenAirInterface LTE/LTE-A emulation platform, demonstrate that main delay bottleneck resides in the uplink synchronization of the UE to the target eNB.