Selection of fastest speed grade of Zynq in Vivado
xc7z030fbv484-3,
xc7z030fbv676-3, 
xc7z030ffg676-3, 
xc7z030ffv676-3


Usually -3 (pronounced as Dash 3 device) devices are faster and premium cost too!!.Each speed grade will have different number of IO pins variation, if u look at the 484,676 they are denoting the number of IO pins available in the device and for the user usually will get the 65% of the mentioned pins remaining pins will be for power(vcc/gnd) and some dedicated pins like mode pins,jtag pins,done,program_b pins. Based on the user requirement for the IOs in the design u can select the device .. But as the IO count increases the device cost also increases.


  fbv,ffg,ffv


these are the package types of the devices. User can go through the family data sheet(23rd page) and can understand which type package user required.