Need help understanding behavior of Claymore with 2 Graphics cards

I have 2 old graphics cards (I am testing code while new cards where ordered)

AMD Radeon HD 7800 (x2)

When i have both cards in the machine and run NsGpuCNMiner.exe GPU 0 gets 25 h/s, but GPU 1 gets 336 h/s.

If I take out GPU 0 and run with Just GPU 1 it only runs at 55 h/s

I have set all the environment variables correctly per the instructions.

Anyone encounter this before - or if you know what I am doing wrong, please let me know!

Thanks,
Chris