Turning on some optimizations in Quartus II may help increase it. Here are some you may want to try:
a.) Change the optimization technique to Speed • Click Assignments -> Settings • Select Analysis & Synthesis Settings • For Optimization Technique, select Speed
b.) Turn on one-hot state machine processing • Click Assignments -> Settings • Select Analysis & Synthesis Settings • For State Machine Processing, select One-Hot
c.) Turn off Multiplexer Restructuring • Click Assignments -> Settings • Select Analysis & Synthesis Settings • For Restructure Multiplexers, select Off
d.) Turn on Physical Synthesis in the Fitter • Click Assignments -> Settings • Expand Fitter Settings by clicking the + symbol next to it. • Select Physical Synthesis Optimizations • Check Perform physical synthesis for combinational logic • Check Perform register duplication • Check Perform register retiming • Select Normal for Physical synthesis effort
