The 7 has a DisplayPort and two HDMI connectors (for the integrated graphics) and also has 4 more back panel USB 3.0 ports and a back panel optical digital audio connector. It also has 2 additional SATA 6gb/s ports.
The 5 has a VGA, DVI and HDMI port (for integrated graphics) and no digital audio out and less USB 3.0 ports and less SATA 6gb/s ports.
Those are the main differences.