Timing closure problems in Quartus 12.0sp2

Thanks for the feedback.

I've been compiling these projects (the issue occurs on multiple projects) in 11.1 for several months and haven't seen any timing violations across a large number of builds. Typically I see a positive slack of 0.7ns or so.

Switching to 12.0 I just rebuilt all my projects and about half of them are failing timing. I tried doing a quick seed sweep in the 12.0 DSE on one of them, but it wasn't able to meet timing at any of the seeds I used. I'm trying a seed sweep in DSE again at the highest effort level, but that will take a while.

Something is definitely different in 12.0sp2 that's causing worse results the 11.1. On the plus side it's faster, so I'm assuming that they adjusted some algorithms to speed up compile time at the cost of design performance. I'm hoping there's a setting to go back to the older method so I won't have to switch back to 11.1