The Raspberry Pi contains a /boot/config.txt
.
This file is read by the GPU before the ARM core is initialised. It can be used to set various system configuration parameters. Which can be used for overclocking.
WARNING: Setting any of the following parameters which over volt your Raspberry
Pi will set a permanent bit within the SOC and your warranty is void.
So If you care about the warranty do not adjust voltage.
|:---------------------|------------------------------------------------------:|
| Option | |
|:---------------------|------------------------------------------------------:|
| arm_freq | frequency of ARM in MHz. Default 700.
| gpu_freq | Sets core_freq, h264_freq, isp_freq, v3d_freq
| | together.
| core_freq | frequency of GPU processor core in MHz. Default 250.
| h264_freq | frequency of hardware video block in MHz. Default 250.
| isp_freq | frequency of image sensor pipeline block in MHz.
| | Default is 250.
| v3d_freq | frequency of 3D block in MHz. Default 250.
| sdram_freq | frequency of SDRAM in MHz. Default 400.
| over_voltage | ARM/GPU core voltage adjust. [-16,8] equates to
| | [0.8V,1.4V] with 0.025V steps. Default 0 (1.2V) [1]
| over_voltage_sdram | Sets over_voltage_sdram_c, over_voltage_sdram_i,
| over_voltage_sdram_p together
| over_voltage_sdram_c | SDRAM controller voltage adjust. [-16,8] equates to
| | [0.8V,1.4V] with 0.025V steps. Default 0 (1.2V) [1]
| over_voltage_sdram_i | SDRAM I/O voltage adjust. [-16,8] equates to
| | [0.8V,1.4V] with 0.025V steps. Default 0 (1.2V)[1]
| over_voltage_sdram_p | SDRAM phy voltage adjust. [-16,8] equates to
| | [0.8V,1.4V] with 0.025V steps. Default 0 (1.2V)[1]
|:----------------------------------------------------------------------------:|
From the elinux wiki.