$ sudo nano /boot/config.txt

#----- Zero OC -----
##fake_vsync_isr=1
##framebuffer_swap=0
##gpu_mem=48
##init_emmc_clock=100000000

force_turbo=1

##arm_freq=1150
##arm_freq=1100
##arm_freq=1095 for my other unit with heatsink
##arm_freq=1085
arm_freq=1050

##gpu_freq=550 for the unit with a heatsink
##gpu_freq=530
gpu_freq=520
##gpu_freq=300

##core_freq=560
#core_freq=555
##core_freq=532
core_freq=500
##core_freq=440
over_voltage=3

sdram_freq=533
over_voltage_sdram=1
##over_voltage_sdram_c=7
##over_voltage_sdram_i=7
##over_voltage_sdram_p=8

dtparam=sd_overclock=100
#dtparam=sd_overclock=125