Does repeater/retimer be need when Arria10 GX FPGA used in backplane application?

two boards are assembled on a backplane with a distance about 50cm. Two Arria10 GX FPGAs are located on these two boards seperately, connecting to each other with Arrria 10 GX transceiver。Does repeater or retimer be need in this application? The data rate is about 6~8Gbps。