RPi Easy SD Card Setup - eLinux.org

over_voltage
over_voltage_sdram
over_voltage_sdram_c
over_voltage_sdram_i
over_voltage_sdram_p
force_turbo
initial_turbo
arm_freq_min
core_freq_min
sdram_freq_min
over_voltage_min
temp_limit
current_limit_override
force_turbo mode
force_turbo=0
ARM/GPU core voltage adjust. [-16,8] equates to [0.8V,1.4V]
with 0.025V steps. force_turbo will allow values higher than 6.
Default 0 (1.2V) [5]
Sets over_voltage_sdram_c, over_voltage_sdram_i,
over_voltage_sdram_p together
SDRAM controller voltage adjust. [-16,8] equates to
[0.8V,1.4V] with 0.025V steps. Default 0 (1.2V) [5]
SDRAM I/O voltage adjust. [-16,8] equates to [0.8V,1.4V]
with 0.025V steps. Default 0 (1.2V) [5]
SDRAM phy voltage adjust. [-16,8] equates to [0.8V,1.4V]
with 0.025V steps. Default 0 (1.2V) [5]
Disables dynamic cpufreq driver and minimum settings below.
Enables h264/v3d/isp overclock options. Default 0
Enables turbo mode from boot for the given value in seconds
(up to 60) or until cpufreq sets a frequency. Can help with
sdcard corruption if overclocked. Default 0 [6]
Minimum value of arm_freq used for dynamic clocking.
Default 700
Minimum value of core_freq used for dynamic clocking.
Default 250
Minimum value of sdram_freq used for dynamic clocking.
Default 400
Minimum value of over_voltage used for dynamic clocking.
Default 0
Overheat protection. Sets clocks and voltages to default when
the SoC reaches this Celsius value. Setting this higher than
default voids warranty. Default 85
Disables SMPS current limit protection when set to
"0x5A000020". Can help if you are currently hitting a reboot
failure when overclocking too high. [7]