You could try!
Hmmm... That 9400m sounds quite familiar...
lemme guess, New Gen Macbook? =P
To get to the point, yeah, you could try overclocking your 9400m. Here is a link to "NVIDIA nTune 5.05.54.00"
http://www.nvidia.com/object/ntune_5.05.54.00.html
This is what you'll need to...