Good equipment that partly reaches the performance limit, ie running multiple apps parallel then occur partly significant delays. However, for me is the dual SIM function in the foreground. Operation of the 2 simcards (D1 and D2) runs flawlessly so far. Depending on network availability has either Sim1 or Sim2 priority on 3G or GSM. The lower power or unavailable number do I forward to the other card. Have the workplace no D1 reception, then everything goes on D2, at home it's vice versa. Once there, I switch on Sim1 and 3G. Other network provider as the D-nets come experience shows out of the question. It can both sim slots 3G, just not in parallel but which also. A data connection should be enough.
