Have you done any testing as to which adders provide the best increase to the fmax? In order to get multiple cores in there going to need to pick and choose which adders to replace with dsps and which not to. I'm currently at 66% LUT usage with 99% memory LUT and 108% dsp usage with 2 unrolled cores (I had one core do even nonces while the other does odd nonces to make life easy). I've been slowly working down the number of dsps utilized per core to make it fit. I'm thinking it might be possible to get 3 full cores on the A7 200.

Does the DSP performance increase compound? If I change one adder over to DSP utilization and it gives a 10% fmax increase... would changing additional adders down the chain affect that 10%? or will that one adder always give a 10% boost? I'm wondering if it will be possible to go through the adders one by one and calculate the increase in frequency for each one to find which adders would be the most effectively utilized under DSP48 blocks to get the best timing.