Design begining phase..

I assume, that you didn't want to rate the profound forum discussion as blah, blah.

You can use performance overview data given in the datasheet as a rough estimation what can be achieved. If you have already done FPGA designs, you'll probably know that in advance for a particular device family.

If you are new to FPGA design, you should realize critical parts of your design on an evaluation platform. You also try to judge from simulation only, if a design can be realized, but I wouldn't suggest it.