Timing issues using Arria 10 Dev kit for massive design

Hi, i'm working with a huge design using Arria 10 Dev kit and i'm facing with timing issues after signoff analysis. These time issues are associated specially with DSP blocks where long combinational paths are reported. So, the first idea would be redesign long combinational paths, but, in case of this solution is bad for design performance, the second idea would be apply a good floorplan, just to help Quartus solve timing issues. And, I'm in second option, trying to do the best floorplaning as possible. What can you suggest to do more? The design still have time violations for DSP blocks....