Raspberry Pi 2 extream overclocking


13 posts
by Zen1 » Sat Apr 11, 2015 8:08 pm
So, I've been working on this project for a while and I just wanted to share my results as there hasn't been much interest in overclocking the BCM2836. Today I managed to overclock my Pi 2 to 1500MHz and I just wanted to share to see if anyone else was interested. I removed L3 and soldered a lead on to the pad nearest C7 so that I could apply a separate core voltage. Using the software overvoltage setting of 8 only brings you up to 1.4V. I used an EVGA epower unit to provide a clean 1.66V. I used liquid nitrogen to cool the chip with a custom made CPU pot I designed. I had to use an extension cable for the SD card as it was getting too cold and I applied a heating pad to the bottom of the board to assist with keeping the RAM warm and defrosting the board. I found the chip coldbugs at -130C and refuses to boot under -90C. I found keeping the ram above 20C helped a lot with booting and stability.
So this is just a teaser to see if there is any other interest out there and to see if anybody knows of anyone who has gone further than this.
My benchmark can be found here:
http://hwbot.org/submission/2823857_zen ... 025.77_pps
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by expandables » Sun Apr 12, 2015 2:14 am
Nice same to be very cool :mrgreen:
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by hojnikb » Sun Apr 12, 2015 8:57 am
How far can you push it on 1.4V voltage ? :?:
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by Zen1 » Sun Apr 12, 2015 4:09 pm
hojnikb wrote:How far can you push it on 1.4V voltage ? :?:

Using force_turbo=1 I was able to get to 1200. Two notes on that overclock: First, I could not push it any further with an over-voltage of 8 vs 6. Secondly, I could not get it to boot at anything above -30C. You may be able to use difluoroethane(air duster) to replicate this as it has a boiling point of -25C(have good ventilation and find cans that don't have a bitterant).

force_turbo=1
arm_freq=1200
start_x=0
core_freq=600
sdram_freq=500
over_voltage=6
gpu_mem=256
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by dom » Sun Apr 12, 2015 5:25 pm
I know the 1.8V supply runs pretty close to the core voltage (the 1.2V-1.4V supply), and James Adams had a pretty neat mod to run the core voltage off the 1.8V supply...
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by Zen1 » Sun Apr 12, 2015 9:20 pm
dom wrote:I know the 1.8V supply runs pretty close to the core voltage (the 1.2V-1.4V supply), and James Adams had a pretty neat mod to run the core voltage off the 1.8V supply...

Duh! Why didn't I think of that?!? Thanks for the idea! :D
I couldn't go any higher on the epower unit because I don't have the evbot to interface with it.
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by Zen1 » Sun Apr 12, 2015 10:34 pm
I just soldered in a removable jumper between the 1.8V rail and the Vcore. I won't be able to test it until sometime later this week. I also have some low ESR caps if power delivery from the 1.8V rail is insufficient. My goal here is to hit the 1800MHz mark, but considering the power I've already put into it, I feel 1.8 won't be enough for that 200% mark. I'll keep you guys posted.
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by SteveRPi » Mon Apr 13, 2015 6:47 am
This person documents overclocking Ppi2 to 1200 MHz using a standard set-up:

http://linuxonflash.blogspot.com.au/201 ... mance.html

My RP2 is stable at 1100 MHz, using a standard 1A(? I think) power supply, no force-turbo required:
[Rpi2:~]$ ./cpustatus.sh
Temperature: 44.9 C
Voltage: 1.39 V (+0.19 overvolt)
Min speed: 600 MHz
Max speed: 1100 MHz
Current speed: 1100 MHz
Governor: ondemand

/boot/config.txt
arm_freq=1100
core_freq=550
sdram_freq=483
over_voltage=4

Using the same instructions, I have managed to boot to 1166 MHz, but it is less stable.

Steve.
PS: apologies for repetition from another thread.
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by Zen1 » Mon Apr 13, 2015 8:09 am
SteveRPi wrote:This person documents overclocking Ppi2 to 1200 MHz using a standard set-up:

http://linuxonflash.blogspot.com.au/201 ... mance.html

My RP2 is stable at 1100 MHz, using a standard 1A(? I think) power supply, no force-turbo required:
[Rpi2:~]$ ./cpustatus.sh
Temperature: 44.9 C
Voltage: 1.39 V (+0.19 overvolt)
Min speed: 600 MHz
Max speed: 1100 MHz
Current speed: 1100 MHz
Governor: ondemand

/boot/config.txt
arm_freq=1100
core_freq=550
sdram_freq=483
over_voltage=4

Using the same instructions, I have managed to boot to 1166 MHz, but it is less stable.

Steve.
PS: apologies for repetition from another thread.

Great find. I haven't had the time to collect as much data as I would like to. The guy in your link did a great job. It looks like his data is in line with yours. He was able to boot at 1166, but was only able to get it stable at 1100. I wonder if I could create a script to automatically bench and collect data as it is so time consuming to do manually. Something with privileges that could automatically tweak values and reboot... Just thinking out loud. Thanks for the clocks as well. I'll have to figure out an elegant way to collect and display data, maybe a box-plot with successful clocks vs voltage.

Just another thought, is the RPi 2 capable of going to 1.4V(over_voltage=8) without using force_turbo or current_limit_override? I thought you could only go up to 1.35V(over_voltage=6) without those.

Last thought before I run off to bed. Does anyone know how to get OpenArena working as a benchmarking platform? There are a lot of guides out there but they seem to be dated and don't work anymore. OpenArena still works, but I can't get it to count FPS and total frames rendered.
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by Kealper » Mon Apr 13, 2015 7:46 pm
Last thought before I run off to bed. Does anyone know how to get OpenArena working as a benchmarking platform? There are a lot of guides out there but they seem to be dated and don't work anymore. OpenArena still works, but I can't get it to count FPS and total frames rendered.


Record or aquire a demo/replay file for it and then open the console (~) and type:

Code: Select all
timedemo 1


Once you've enabled timedemo mode, load up the demo and let it run, it'll play back the specified demo as fast as the system will let it, and at the end it'll print out some basic statistics into the console, such as the average framerate and total time it took to display all frames in the chosen demo.

Also make sure timedemo mode is disabled before trying to actually play the game, it gets a bit angry.
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by Afonso » Fri Aug 26, 2016 9:30 pm
Nice OC!
Sorry for being late but I'm gonna ask it anyway.
Do you know if there's another way to overcome the 1.4 V limit without having to buy the EVGA power board?
Thanks
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by dom » Mon Aug 29, 2016 10:03 am
You can get about 1.6V with this board mod:
https://www.raspberrypi.org/forums/view ... 50#p765205
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by GamingStar » Fri Dec 23, 2016 9:37 pm
Zen1 wrote:~snip~

force_turbo=1
arm_freq=1200
start_x=0
core_freq=600
sdram_freq=500
over_voltage=6
gpu_mem=256

I used those settings on my RPi2 and my pi started to emit sparks ;-;
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