I don't see much of a difference with ccminer. I am still getting 6.8./6.9 Mhash.

Here is my config: nvminer.exe -d 0,1 -a dmd-gr -o stratum+tcp://dmdpool.digsys.bg:3333 -u user -p pass

Any additional flag that you are using to get 7.8? Or perhaps are you overclocking the card?