Overclock question

lowridin_guy

New member
May 10, 2012
339
0
0
Does increasing core_freq make a big impact in performance on the pi? I am currently using the default OC settings based on Tuxen's image and have played around with increasing arm_freq and I notice a little bit of an improvement but nothing major (went up to 900).

Just curious if increasing core_freq would make a bigger difference. I had heard to leave this at 250 since it could cause corruption in SD cards in many cases.

Thanks!
 

jas0npc

Banned
May 5, 2012
2,449
0
0
UK
I have an older pi board 256m, I could never get it past 900, got a usb3 pen drive now its rock steady and stable oc at 1000 450 450 6 had no failures, perfect
 

lowridin_guy

New member
May 10, 2012
339
0
0
Yeah I know with a USB install you can OC MUCH higher.

Just wondering about the OC settings on a SD card unit only. I know it differs from pi to pi but just curious if anyone has had a lot of luck with a certain OC setting that is higher than what is default in Tuxen's image.
 

Frederick_99

New member
Sep 18, 2012
452
0
0
UK
Im using

arm_freq=900
core_freq=333
sdram_freq=450
over_voltage=2

force_turbo=1

only with SD card and never experienced any issues with corruption, but don't know if this is higher than Tuxens settings.

RPi is Rev2 512Mb.
 

Mcord

New member
Nov 30, 2012
135
0
0
for some reason for me my Pi does not like over voltage of 6. Causes crashes. I am running off of my external hard drive and have it overclocked like frederick
 

Hustler

New member
Mar 24, 2013
78
0
0
Florida
openELEC
Tuxens w/ addons
arm_freq=900
core_freq=333
sdram_freq=450
over_voltage=2

force_turbo=1

No problems with this image.
Have had a raspbmc corruption at these clock speeds. Trying to figure how to fix w/o eracing it

I want to do the usb 3.0 next. Want to know if I can get it to work without the sd card? And I have also read that usb wont update correctly ?
 
Last edited:

nothere

Banned
Nov 25, 2012
1,036
0
0
arm_freq=1250
core_freq=500
sdram_freq=500
over_voltage=6
force_turbo=1

Using 2gb unbranded class 4 sd card and sandisk usb3 stick (Raspbmc)

Update works fine. No corruption ever for me.
 

nothere

Banned
Nov 25, 2012
1,036
0
0
openELEC
Tuxens w/ addons
arm_freq=900
core_freq=333
sdram_freq=450
over_voltage=2

force_turbo=1

No problems with this image.
Have had a raspbmc corruption at these clock speeds. Trying to figure how to fix w/o eracing it

I want to do the usb 3.0 next. Want to know if I can get it to work without the sd card? And I have also read that usb wont update correctly ?
You will always need an sd card. The pi needs it to boot.
 

nothere

Banned
Nov 25, 2012
1,036
0
0
I am using a 16GB class 10 sd card and USB stick 16GB..........when you update do you have to change your overclocking back to normal and then update?.....or can you just put the 4 files in the update folder and go?
When I used openelec I either used the dev tool or manually copied the files as you said with no issues. As im using Raspbmc at the moment I let that take care of any updates (which also work fine) I never change my overclock settings.
 

Izzie

New member
Mar 28, 2013
31
0
0
Kent, UK
arm_freq=1250
core_freq=500
sdram_freq=500
over_voltage=6
force_turbo=1

Using 2gb unbranded class 4 sd card and sandisk usb3 stick (Raspbmc)

Update works fine. No corruption ever for me.
Metal how hot does your Pi get running it with that overclocked so high ? and do you use any thing to help cool it ?
 

nothere

Banned
Nov 25, 2012
1,036
0
0
It never reaches the 80c limit (gets damn close tho), you can however disable the 80c reboot limit. Its in a case with no additional cololing.
 

Izzie

New member
Mar 28, 2013
31
0
0
Kent, UK
wow no additional cooling and it doesn't hit the reboot limit now that is surprising, I want to have a go at overclocking mine more at some stage but need to get a better case as it feels like it gets a little to warm on the bottom in the supposed adafruit case.
 

tuxen

Banned
Mar 23, 2012
2,235
0
0
Denmark
Increasing the core_freq will give you a the biggest boost as this also controls the level2 cache of the arm processor.
I have mine at 500 when I had a 256MB board I could go to 450 also I NEVER had a sdcard corruption due to overclocking on any of my 3 sdcards I use, but yes I have heard about it. Just make sure you back it up using win32imager or USBit first until you know if your sdcard is prone to this behavior.
 
Last edited:

tuxen

Banned
Mar 23, 2012
2,235
0
0
Denmark
It never reaches the 80c limit (gets damn close tho), you can however disable the 80c reboot limit. Its in a case with no additional cololing.
It's 85c so you have a little more slack. Besides disabling it you can also adjust it. :)
1250 is impressive mate. 1150 is my limit it doesn't nessesarily depends on heat/overvolt alone though.
I run the arm at 1050 can't really see a difference in fps/response in the XBMC GUI between 966 and and 1150 I'd rather raise my core more than 500 I tried 600 this gave a kick in the GUI fps/response but crashed after 10mins. Heh.. I also tried to disassociate the calculation from core freq to h264/v3d/isp that did not go well either. Maybe you can squeeze something from this, I know! It IS quite geeky and on the edge of sanity if not on the other side lol.

To explain :)

Quote: "Clocks relationship

The GPU core, h264, v3d and isp share a PLL, therefore need to have related frequencies. ARM, SDRAM and GPU each have their own PLLs and can have unrelated frequencies.[9]
The following is not necessary with "avoid_pwm_pll=1".
Code:
pll_freq = floor(2400 / (2 * core_freq)) * (2 * core_freq)
gpu_freq = pll_freq / [even number]
The effective gpu_freq is automatically rounded to nearest even integer, so asking for core_freq=500 and gpu_freq=300 will result in divisor of 2000/300 = 6.666 => 6 and so 333.33MHz."

-
You probably know all this so the post is not especially directed at you but to all with the curiosity. :)
Source: http://elinux.org/RPi_config.txt
 
Last edited: