For what it's worth, I used 5SGXEA7H1F35C1 and got 11% utilization (~8 cores?), and Fmax >200MHz.
BTW: was this the design found in the rtl directory or in some of the projects?
I will try to re-run it as my timing result can't be correct...
It sounds like you have since sorted it out, but yes I was using a cloned DE2-115 project which refers to the common ../../src/xxx.v
I just changed the target device and created a new PLL.