DDJ RX

Hi I have a 2 month old DDJ RX running the latest firmware & version of rekordbox, laptop is also a 2 month old late 2013 macbook pro 13 from apple & only used for rekordbox. When using rekordbox and going thru my songs or folders its very very very slow to resopond sometimes also when i instant double a track on other deck it works only when it wants to? Also the biggest problem is after playing for a period of time could be 5mins or half an hour the music cuts of like i have disconected the usb cable but the controler still responds? But it makes a disconection sound on in speakers? Anyone any ideas?