rekordbox cfx and combo FX slow at responding?

i have a 2.4 GHz Intel Core i7, 16 GB 1333 MHz DDR3 RAM, with a SSD. so my Mac is really fast. I'm guessing it's a software problem but the colour affects are very slow at responding on a DDJ-RZX. also the combo FX freezes.

Is anyone having the same problem as me? If so is there any way around it?

thanks from Marcus