What are the overclocking capabilities?

Question

I've not ordered mine (yet!), but I do some overclocking as a hobby to the extent that my netbook, Android phone, desktop, and even my wife's Blackberry are overclocked.

Is there potential to overclock the RPi beyond stock voltage and speeds?

I figure I can rig some sort of custom cooling if need be.

If my Pi won't boot when I overclock it, how do I come back to the previous state? Do I have to backup the whole SDCard at each step? Thanks. — Xavier Nodet, Jul 26 '12 at 19:29
@XavierNodet, maybe you should ask your own question? It will get more attention on here. — Kyle Macey, Jul 26 '12 at 21:45
Done, with answer... http://raspberrypi.stackexchange.com/questions/1338/easiest-way-to-return-to-a-known-good-state-when-overclocking — Xavier Nodet, Jul 29 '12 at 18:07

score 30 · Accepted Answer · edited Jun 18 '12 at 10:53

30

Without overvoltage (i.e. at the default 1.2V), most Pis can run at up to 800MHz stably.

With overvoltage, 1000MHz is common.

WARNING: Setting any of the 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.

References:

edited Jun 18 '12 at 10:53

Jivings

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answered Jun 12 '12 at 22:10

finnw

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I read your references and I don't see evidence that 1GHz is common with over voltage. – LovesTha Jun 12 '12 at 23:05
I have not seen that figure for overvolting before but it seems about right for overclocking. The raspberry pi foundation and distributors do support overclocking but not overvolting. – Shane Hudson Jun 13 '12 at 13:50
Sorry I cannot remember the forum thread where I read that figure, it's not the one I linked. – finnw Jun 13 '12 at 16:33

score 13 · Answer 2 · answered Jun 18 '12 at 11:05

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.

score 9 · Answer 3 · answered Jun 12 '12 at 22:07

There are a list of confirmed clock speeds achieved which would save you some time: http://elinux.org/RPi_config.txt#Overclocking_options so someone has managed 1000MHz with some overvolting applied, of course this invalidates your warranty so maybe stock up on a few :)

score 1 · Answer 4 · answered Jun 21 '14 at 23:13

I overclocked mine without touching the voltage for a long time:

arm_freq=940
gpu_freq=380
sdram_freq=530
overvoltage=0

I tested these values with quake and my rpi never crashed with this oc.

After trying it with voltage I got these values. They are "floored" because I didn't want to reboot everytime for every 10MHz.

arm_freq=1000
core_freq=500
sdram_freq=600
overvoltage=2

This might not run stable with quake3 but is rocksolid as Spigot (Minecraft) server.

It's a UK-built Model B from late 2013 (got it last christmas :D). Just to be more precise what hardware we are talking about.

Maybe I should also add that I mainly use my old Dell Venue Pro's power supply with 5V and 1A :) — ecth, Jun 22 '14 at 10:10

score 1 · Answer 5 · answered Aug 07 '13 at 14:58

1

I am currently using:

arm_freq=1100
sdram_freq=600
overvoltage=12
core_freq=500

The highest temperature my CPU has ever reached is 61 degrees. However the overclocking capabilities change depending on the manufacturer and batch.

answered Aug 07 '13 at 14:58

Matthew

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What are the overclocking capabilities?

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