Why are there large resource differences with different optimization mode?

In the Intel® Quartus® Prime Pro Edition Software, you might find that the ALM utilization rate is much higher when enabling "Superior performance effort" compared to "High performance" optimization mode. Synthesis optimizations can have a very large impact on the tradeoff area vs. performance.

The netlist optimizations in Synthesis result in significantly more ALUTs for Superior Performance. You can turn on the optimization option "Restructure Multiplexers" and disable "Timing-Driven Synthesis" when you enable the “Superior performance” optimization mode, which can help to reduce synthesis area. Your design might fail to fit this optimization mode if the logic utilization is high.