They cannot be used at the same time depending on the conditions.

ALTGX adopts RBC (Rule Base Configuration), and there are certain rules depending on the setting items.

Please refer to the chart on page 110 of the URL link below regarding ALTGX.

 https://www.altera.com/en_US/pdfs/literature/hb/stratix-iv/stx4_siv52001.pdf

For example, P116 is a setting chart of Double-Width Mode, but when Rate Match FIFO is Enable, Byte Ordering can only be selected as Disable.

If the Rate Match FIFO and Byte Ordering Block functions cannot be selected at the same time, for example, the Byte Ordering function must be implemented in the user circuit.