how to go above max freq ?

In an interview question, they asked me how to go above max frequency of the FPGA?

I understand that max frequency is related to the fabrication method or technology of the FPGA, so I said increasing throughput, which is basically increasing from processing 1 pixel at the time to 2 pixels for an ISP example. BUT he said ok but did not say what was the answer.

Which I can think about techniques to work with DDR ?

What do you think ?