For UltraScale and UltraScale+ devices, at line rates above 16.375
Gb/s, QPLL0 uses refclk0 and QPLL1 uses refclk1. This is a limitation of the transceiver. When the 24.330G and under line rate option is selected, this check box
displays which QPLL is being used depending on which refclk has been selected.