FMAX Problem

Hello,

I have a customboard design that uses the Cyclone EP1C20F324C7 device. Before I created my circuit board I created my design and let Quartus assign the pins, and I was able to achive an FMAX of 80MHZ (this was my goal)

The problem is, when I locked in the pins that Quartus assigned in the Assignment editor, my FMAX decreases to about 68Mhz.

Any help would be greatly appreciated!

Brandon