Compare other G750JX scores and see where you are lacking. Without a very detailed look it seems to me your GIMP and OpenCL scores are a little low.
Check your OpenCL drivers are installed correctly.
Switch to high-performance mode
Try memory with tighter timings (you'll have to buy new though as our G-series BIOS does not offer memory timing adjustments, so not really worth it just for a faster number)
Maybe search for some software that can tweak the base clock a few notches to 101/102MHz. We don't provide this for notebooks sorry.