When you have two 
	 micro SIM cards inserted on your phone, only one card can connect to the 3G network. The other card will connect to the 2G network only. 
	 You can set which card you want to connect to the 3G network. 
	 
 
  
 
	 -  
		  Go to 
				Settings. 
			  
		
 
-  
		  Tap 
			 Mobile networks. 
		   
		
 
-  
		  Tap 
			 . 
		   
		
 
-  
		  Choose the card you want to connect to the 3G network.