Difference between revisions of "RPi Overclocking"

From eLinux.org
Jump to: navigation, search
(fix grammar, make default values more obvious with separate column)
(Redirected page to RPiconfig#Overclocking)
 
(One intermediate revision by one other user not shown)
Line 1: Line 1:
=Overclocking configuration=
+
#REDIRECT [[RPiconfig#Overclocking]]
'''WARNING:''' Setting any (of the below) parameters which could potentially over-volt your Raspberry Pi, will set a ''permanent bit'' within the SOC, voiding your warranty.  So if you care about the warranty on your Raspberry Pi do NOT adjust any voltages!
 
 
 
Also at your own risk, you can try the display [[RPi_config_for_your_TV|overscan settings]] from our wiki. These overscan-settings were [http://www.raspberrypi.org/forum/features-and-requests/should-we-make-a-wiki-page-for-overscan-settings posted] on the forum, but are not confimed to work...
 
 
 
==Overclocking options==
 
 
 
These settings are also documented in one of the example configuration files mentioned on [[RPi_config.txt|the config page]].
 
 
 
{| class="wikitable"
 
!Option !! Description !! Default
 
|-
 
!align="right"|arm_freq
 
| frequency of ARM in MHz.
 
| 700
 
|-
 
!align="right"|gpu_freq
 
| Sets core_freq, h264_freq, isp_freq, v3d_freq together.
 
| See below
 
|-
 
!align="right"|core_freq
 
| frequency of GPU processor core in MHz. Note that it has an impact on ARM performance because it drives the L2 cache.
 
| 250.
 
|-
 
!align="right"|h264_freq
 
| frequency of hardware video block in MHz.
 
| 250
 
|-
 
!align="right"|isp_freq
 
| frequency of image sensor pipeline block in MHz.
 
| 250
 
|-
 
!align="right"|v3d_freq
 
| frequency of 3D block in MHz.
 
| 250
 
|-
 
!align="right"|sdram_freq
 
| frequency of SDRAM in MHz.
 
| 400
 
|-
 
!align="right"|over_voltage
 
| ARM/GPU core voltage adjust. [-16,8] equates to [0.8V,1.4V] with 0.025V steps. <ref name=voltages>What this means is that you can specify -16 and expect about 0.8V as the GPU/core voltage. This is 0.4V below the normal value of 1.2. If you specify 16, you'd get 0.4V ABOVE the normal value of 1.2V, or 1.6V. The fact that someone carefully specified "8" and "1.4V" as the upper limit in the examples leads me to think that it is likely to shorten the life of your raspberry pi significantly if you would specify values above "8".  So: don't specify values above zero, but if you do, don't go above 8.</ref>
 
| 0 (1.2V)
 
|-
 
!align="right"|over_voltage_sdram
 
| Sets over_voltage_sdram_c, over_voltage_sdram_i, over_voltage_sdram_p together
 
| See below
 
|-
 
!align="right"|over_voltage_sdram_c
 
| SDRAM controller voltage adjust. [-16,8] equates to [0.8V,1.4V] with 0.025V steps.
 
| 0 (1.2V)<ref name=voltages />
 
|-
 
!align="right"|over_voltage_sdram_i
 
| SDRAM I/O voltage adjust. [-16,8] equates to [0.8V,1.4V] with 0.025V steps.
 
| 0 (1.2V)<ref name=voltages />
 
|-
 
!align="right"|over_voltage_sdram_p
 
| SDRAM phy voltage adjust. [-16,8] equates to [0.8V,1.4V] with 0.025V steps.
 
| 0 (1.2V)<ref name=voltages />
 
|}
 
 
 
== Clocks relationship ==
 
 
 
ARM, SDRAM and GPU each have their own PLLs and can have unrelated frequencies<ref name=freq_relationship>http://www.raspberrypi.org/phpBB3/viewtopic.php?f=29&t=6201&start=125#p126308</ref>.
 
The GPU core, h264, v3d and isp share a PLL, so need to have related frequencies. PLL will be set to:
 
pll_freq = core_freq * 2^n, for smallest n satisfying pll_freq > 600MHz.
 
 
 
GPU core, h264, v3d and isp should all be integer divisors of pll_freq.
 
So core_freq=480 sets pll_freq=960. That would allow a v3d_freq/h264_freq/v3d_freq of 320 with an integer divider of 3.
 
 
 
==Tested values==
 
The following table shows some successfull attempts of overclocking. These settings may not work on every device and can shorten the life of the Broadcom SoC. '''Warranty will be voided if overvoltage is used.'''
 
{| border="1"
 
! arm_freq !! gpu_freq !! core_freq !! h264_freq !! isp_freq !! v3d_freq !! sdram_freq !! over_voltage !! over_voltage_sdram
 
|-
 
|750 ||255 || || || || ||450 || ||
 
|-
 
|900 ||250 || || || || ||500 || ||
 
|-
 
|900 ||275 || || || || ||500 || ||
 
|-
 
|900 || ||450 || || || ||450 || ||
 
|-
 
|930 ||350 || || || || ||500 || ||
 
|-
 
|1000 || ||500 || || || ||450 ||6 ||
 
|-
 
|1000 || ||500 || || || ||500 ||6 ||
 
|}
 
 
 
=References=
 
<references/>
 
 
 
{{Template:Raspberry Pi}}
 
[[Category:RaspberryPi]]
 

Latest revision as of 13:41, 1 December 2012