Due to a problem in the Intel® Quartus® Prime Standard/Pro Edition software version 17.1/18.0 and Intel® Quartus® Prime Standard Edition software version 18.1, the synthesis may not infer the use of DSP coefficients ROM correctly if you set AUTO_RAM_RECOGNITION and AUTO_ROM_RECOGNITION OFF. This results in low Fmax of FIR II IP core.
To work around this problem in the Intel® Quartus® Prime Standard Edition software, follow the steps below.
Set Assignments > settings > compiler settings > Advanced settings(Synthesis) > Auto RAM Replacement from OFF to ON.
Set Assignments > settings > compiler settings > Advanced settings(Synthesis) > Auto ROM Replacement from OFF to ON.
This Problem has been fixed in Intel® Quartus® Prime Pro Edition software version 18.1.