DDR2-RAM and TSE - How to increase data-rate?

Hello,

I've the following design on my Cyclone III Dev. Board:

- NiosII writes data to DDR2-RAM

- When writing data finishes NiosII activates SGDMA to put all this data to TSE. TSE then transmitted this data...

First I used OnChipMemory instead of DDR2-RAM. I reached an output-rate at TSE round about 80MBytes/sec.

But now I want to use DDR2-RAM with DDR2 SDRAM High-Performance Controller because I have much more data to store. I only reached an output-rate at TSE round about 17MBytes/sec.

What can I do to increase the output-rate of TSE with using DDR2-RAM? Is there any possibility?

Thanks for every hint!

tonib