I am puzzled that your 9800 GT delivers "only" so little hashing power. It has 112 CUDA cores after all! My 9600M GT in the laptop does 9.6 kHash/s on Linux with just 32 CUDA cores.
9800 GT has Compute Capability 1.0
9600M GT has Compute Capability 1.1
https://developer.nvidia.com/cuda-gpusMaybe that's the reason