The way I use my pc is like this, I have a logitech K400r wireless keyboard plugged into the back USB 2.0 port, it works fine just like another wireless keyboard UNTILL I plug in something into the USB 3.0 thats next to it, it can be a USB 3.0 external HDD, a USB 3.0 flash drive, a USB 3.0 HUB, if I plug in anything into the back USB 3.0 port the mouse and keyboard just stop responding and start to lag behind or just not respond at all. As soon as i remove what ever I plugged into the back USB 3.0  port the mouse and keyboard start working like normal. Iv'e tried another wireless logitech keyboard I have and it does the same thing. I have the dongle on a USB extender? ( its a usb type a to a ) and im not that far away from the pc either. I can use the from USB 3.0 and the mouse works just fine, I want to use a USB 3.0 hub but because of this problem I cant. Can some please help me figure out whats wrong with this thing ? 

Specs

Intel Pentium G4400
G skill 8GB of ram 

1 Kingston SSD

Have you tried connecting your Keyboard and mouse through the hub rather than to the PC directly?