Design fits on Cyclone IV but not Cyclone V

I believe the extra fitting attempts have been deprecated, if not disabled. On subsequent fitting attempts, the fitter tries less and less to meet timing, and spends tons of time focusing on routability. Most of the time this occurs it spends a lot of time and still no-fits, and the few times it does fit the results are so bad they're usually useless.

I would recommend:

- Assignments -> Settings -> Fitter ->

Placement Effort = 8

Router Effort Level = Maximum

Optimize Timing = Off(This is the killer for performance)

You might also want to try turning Optimize Hold Timing off, although that's not part of the normal extra fit passes. This would make a design that might not functionally work, but would get a fit(which is what the extra fit passes often do).