The results are quite normal for those cards when mining Cryptonight Coins.
That alogarithm is often optimized for CPU mining.
You can mine them with GPUs but, expect less than mining Ethash.

As far as I know, Cryptonight is good for high end CPU Miners (designed to be "everyone has equal mining opportunity"),
not recommended for a GPU rig.
Better change to another coin using a GPU miner and use a CPU Miner for your CPU to mine that cryptonite coin synchronously.