Hi,
I did a check to see where the time is spent when starting up Wireshark and here’s the findings:
( Win 7 and GTK )
 
Enter main:                               Elapsed time 0us
load_wpcap:                               Elapsed time 0us
Get version strings:                      Elapsed time 10000us
gtk_init:                                 Elapsed time 20000us
gtk_init done:                            Elapsed time 50000us
capture_opts_init:                        Elapsed time 50000us
splash_new: Loading Wireshark...          Elapsed time 50000us
init_open_routines:                       Elapsed time 140000us
Plugins:                                  Elapsed time 140000us
splash_update Initializing dissectors:    Elapsed time 180000us
Call epan_init:                           Elapsed time 190000us
splash_update Register all tap listeners: Elapsed time 411000us
register_all_plugin_tap_listeners:        Elapsed time 422000us
extcap_register_preferences:              Elapsed time 422000us
register_all_tap_listeners:               Elapsed time 2526000us
hostlist_table_set_gui_info:              Elapsed time 2526000us
splash_update Register all preferences:   Elapsed time 2526000us
Load configuration files:                 Elapsed time 2656000us
fill_in_local_interfaces:                 Elapsed time 2656000us
Wireshark is up and ready to go:          Elapsed time 5952000us
 
extcap_register_preferences and fill_in_local_interfaces stands out as the most time consuming activities.
 
Regards
Anders