Cat7 has been double-shielded to meet more stringent specifications.They are better shielded against EMI and crosstalk. The primary difference between Cat6 and Cat7 is the speed and frequency. As you may know, the maximum Cat7 or Cat7a speed is 10.000 Mbit/s, and a Cat6 cable has a maximum speed of 1.000 Mbit/s.
A server rack houses and organizes critical IT systems, which can be configured to support a wide range of requirements. Often called server rack cabinet, it is enclosed to ensure security. Server racks are most commonly found in data center environments, but can also be used in smaller computer closets.