Hi,
The LCD frame frequency is controlled by LCD_GCR.LCLK and other clock source selector/divider. But I think your problem maybe not lies on clock speed or frame speed.
K30's LCD module is same as KM34's LCD module. KM34 has TWR board which has a 1/8 duty LCD panel. Please download a KM34 SDK package. There is a SLCD demo in the package. You can refer to the demo and check your software setting and hardware.
If the problem is still there, you can share your code here. I'll help you to solve it.
Regards,
Jing