How can I improve the DDR3 operation speed?

Hey Guys:

I'm using the DDR3 Uniphy controller on a stratixV board. And now achieved a speed of 800Mhz for memory clock frequency and AFI clk at 200Mhz.

I'm trying to improve the speed to be more faster. Is here anyone who is familiar with this scenario? Can I have any suggestion plz?

Thanks in advance!!

Yumeng