bightf
Posts: 13
Joined: Wed Jun 27, 2012 9:42 am

Re: Overclocking

Tue Dec 11, 2012 4:38 pm

bightf wrote:Hi everybody,

I justed wanted to give you my working OC parameters.
I have a RPi board model B rev 1.0 (so the very first one publicly available) with 256MB Hynix RAM.

These are my current values :
arm_freq=1100
core_freq=500
sdram_freq=500
over_voltage=6
over_voltage_sdram=4

The over_voltage_sdram=4 enables me to reach 500Mhz for the RAM, maybe I could get more with fine tuning and testing...

I've "burned" the CPU (100% usage) for 2 hours, it reached 64°C which I think is reasonable.
My board is enclosed in an RS Components crystal case.

I didn't try quake 3 or any other GPU intensive program, because I use my RPi headless, so I'm gonna give it a try to check whether it's prefectly stable or not.

Oh, and I almost forgot, no SD corruption of any kind at that time, I'll monitor that.
Well, I said that I'd monitor for any SD corruption, and I didn't have to, because the FS got badly corrupted after a random reboot...

And because I didn't backup anything before experimenting, now I have to start all over from a fresh new raspbian image :roll: .

I'm gonna try to lower the frequencies and test again !
A french Raspberry Pi user :)

johnbanks
Posts: 36
Joined: Fri Nov 30, 2012 11:08 pm

Re: Overclocking

Fri Dec 14, 2012 4:04 pm

dom wrote:@poglad

Code: Select all

force_turbo=1
makes overclocking behave like it used to. It won't be dynamic, and you can specific, e.g.

Code: Select all

arm_freq=800
and you get 800 all the time. As long as you don't also overvolt, then this is fine, and won't affect your warranty.
Question regarding arm_freq_min ...
I'm running the today (r12699) version of OPENELEC. vcgencmd get_config shows 1000 and 900 for arm_freq and _min respectively - so no problem with my config.txt I'm assuming.
But dmesg | grp cpufreq shows min of 700000 and max of1000000.
What happened to the arm_freq_min of 900? What am I or Rpi doing wrong?

dom
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 5282
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge

Re: Overclocking

Fri Dec 14, 2012 6:14 pm

johnbanks wrote:I'm running the today (r12699) version of OPENELEC. vcgencmd get_config shows 1000 and 900 for arm_freq and _min respectively - so no problem with my config.txt I'm assuming.
But dmesg | grp cpufreq shows min of 700000 and max of1000000.
What happened to the arm_freq_min of 900? What am I or Rpi doing wrong?
You can't increase arm_freq_min above stock without force_turbo=1 (and possible warranty bit setting).

johnbanks
Posts: 36
Joined: Fri Nov 30, 2012 11:08 pm

Re: Overclocking

Fri Dec 14, 2012 7:09 pm

Thx for the very fast response.
Might help others if a note were added to the RPiconfig-eLinux.org page.
This does mean that arm_freq_min has limited usefulness.
Does it have to be like this? Why not any value up to but not exceeding arm_freq?
Thx again for the great job you're doing

User avatar
poglad
Posts: 100
Joined: Tue Jul 31, 2012 8:47 am
Location: Aberdeen, Scotland
Contact: Website

Re: Overclocking

Mon Dec 17, 2012 11:55 am

dom wrote:
johnbanks wrote:I'm running the today (r12699) version of OPENELEC. vcgencmd get_config shows 1000 and 900 for arm_freq and _min respectively - so no problem with my config.txt I'm assuming.
But dmesg | grp cpufreq shows min of 700000 and max of1000000.
What happened to the arm_freq_min of 900? What am I or Rpi doing wrong?
You can't increase arm_freq_min above stock without force_turbo=1 (and possible warranty bit setting).
Yes, except that that is exactly what I appear to have done...

Edit /etc/init.d/switch_cpu_governor so that after switching to ondemand, it then writes "900000" into file /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq.

Wanderlei
Posts: 79
Joined: Tue Aug 21, 2012 2:01 pm

Re: Overclocking

Sun Dec 23, 2012 5:38 pm

I get corruption on 512MB board without any overclocking.

dom
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 5282
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge

Re: Overclocking

Sun Dec 23, 2012 6:52 pm

Wanderlei wrote:I get corruption on 512MB board without any overclocking.
Does underclocking core_freq fix it (e.g. core_freq=250 and core_freq_min=250)
Is this with multiple sdcards?
Does it happen with latest raspbian image from downloads page?
Can you repeatably corrupt the sdcard? (i.e. image the card, and go through a small sequence of steps and always get corruption?)

Wanderlei
Posts: 79
Joined: Tue Aug 21, 2012 2:01 pm

Re: Overclocking

Mon Dec 24, 2012 8:19 am

dom wrote:
Wanderlei wrote:I get corruption on 512MB board without any overclocking.
Does underclocking core_freq fix it (e.g. core_freq=250 and core_freq_min=250)
Is this with multiple sdcards?
Does it happen with latest raspbian image from downloads page?
Can you repeatably corrupt the sdcard? (i.e. image the card, and go through a small sequence of steps and always get corruption?)
1)I have not explicitly set core_freq to 250, I had no over clocking settings at all because I thought it would default to 250. Are you saying to force it to run at a constant 250 and not let it underclock itself?

2)Yes it happens with different SD cards and power supplies

3)No I have been using OpenELEC, but it has corrupted cards when I used older version of raspbian.

4)Yes
-If I overclock gpu by 1 to 251, first reboot corruption of the second partition ext4 consistently.
-Overclocking cpu to 800 will eventually lead to corruption but not instantly. (gpu at stock)
-With no overclocking it takes a longer amount of time but it will eventually die.

It always happens on reboot. The card has small FAT boot partition and second storage ext4 partition. It almost always the ext4 partition that is affected.

I have tried the exact same SD cards, exact same disk image, exact same power supply on different 256MB board and it not once suffered any form of corruption.

People on the xbmc openelec forum are reporting that 512mb boards that were able to run high overclocks stably and with no corruption have recently encountered that every reboot will corrupted their SD card.

milhouse
Posts: 631
Joined: Mon Jan 16, 2012 12:59 pm

Re: Overclocking

Mon Dec 24, 2012 9:54 am

Wanderlei wrote:People on the xbmc openelec forum are reporting that 512mb boards that were able to run high overclocks stably and with no corruption have recently encountered that every reboot will corrupted their SD card.
Confirming here, I reported it on the XBMC forum (in the OpenELEC thread). In my case, I have a 512MB Pi that has been a great overclocker (1000/500/600/+4/+2/force_turbo=1) with no SD corruption until the OpenELEC Beta series. I've also tested the same Pi/overclock/SD card/PSU with Raspbian, and again no corruption.

Now with the OpenELEC Betas, corruption (of ext4) is a regular occurrence - almost every re-boot and the ext4 partition is stuffed. But prior to the Betas (ie. with the development builds up to r12577, the last I tested), I'd say it was hardly (if ever) a problem, even with the overclock. Again, same overclock, SD card, PSU - just different firmware and OS. Pre-Beta fine, post-Beta SD corruption-happy.

There has been no acknowledgement of these Beta/SD corruption issues from the OpenELEC developers so I've no idea why SD corruption should suddenly rear its ugly head with the Betas, but it frankly means that OpenELEC on Pi is a definite no-go as I have no plans to laboriously fix each and every OpenELEC/Pi installation every time they are booted... although shifting ext4 over to USB would almost certainly help.

Shame, as in all other respects OpenELEC is very good, it's just incapable of surviving more than a single boot... which kind of makes it pretty useless. Would be nice to see some acknowledgement of these issues, as they're frustrating and it's sad to see a regression like this in OpenELEC, particularly when it is ignored.

milhouse
Posts: 631
Joined: Mon Jan 16, 2012 12:59 pm

Re: Overclocking

Sat Dec 29, 2012 7:35 am

dom wrote:
kevs3d wrote:mmc:0 missed completion of cmd 18 DMA (512/512 [1][1]) - ignoring it
I've had that since day one. I've been told it is harmless. We should probably suppress the message.
I've noticed that this message continues to appear with the latest OpenELEC Beta 6 firmware (circa Dec 21 build date) - was it ever suppressed? This is what I'm getting:

Code: Select all

Dec 29 05:37:57 rpi512 user.info kernel: [   24.082686] mmc0: missed completion of cmd 18 DMA (512/512 [1]/[1]) - ignoring it
Dec 29 05:37:57 rpi512 user.info kernel: [   24.082730] mmc0: DMA IRQ 6 ignored - results were reset
Dec 29 05:37:57 rpi512 user.info kernel: [   24.103665] mmc0: missed completion of cmd 18 DMA (512/512 [1]/[1]) - ignoring it
Dec 29 05:37:57 rpi512 user.info kernel: [   24.103709] mmc0: DMA IRQ 6 ignored - results were reset
Dec 29 05:37:57 rpi512 user.info kernel: [   24.104062] mmc0: missed completion of cmd 18 DMA (512/512 [1]/[1]) - ignoring it
Dec 29 05:37:57 rpi512 user.info kernel: [   24.104099] mmc0: DMA IRQ 6 ignored - results were reset
Dec 29 05:37:59 rpi512 user.notice Boot: ### Starting Samba server ###
Dec 29 05:37:59 rpi512 user.notice Boot: ### Starting Avahi Daemon ###
Dec 29 05:38:05 rpi512 user.notice Boot: ### set cpu's to 'ondemand' ###
Dec 29 05:38:05 rpi512 user.info kernel: [   32.465655] bcm2835-cpufreq: switching to governor ondemand
Dec 29 06:02:09 rpi512 user.info kernel: [   32.465675] bcm2835-cpufreq: switching to governor ondemand<6>[ 1475.801351] mmc0: missed completion of cmd 18 DMA (512/512 [1]/[1]) - ignoring it
Dec 29 06:02:09 rpi512 user.info kernel: [ 1475.801398] mmc0: DMA IRQ 6 ignored - results were reset
I'm using a very old 2GB microSD card that seems to pre-date the Class system so it's quite possible the card is a bit slow but I don't really care as OpenELEC runs from RAM and I'm booting from NFS so there are no SD card writes and few reads. However these messages are a tad annoying/disturbing, and I'd rather not see them if they're truly harmless. :)

User avatar
jdmattire
Posts: 1
Joined: Sun Dec 30, 2012 9:26 pm
Location: South Yorkshire, UK
Contact: Website

Re: Overclocking

Mon Dec 31, 2012 3:29 pm

Good afternoon folks,

Got my 512MB Pi for Xmas & like a lot of people I'm trying to get more out of it & managed to get it overclocked to 1100MHz today & its been working flawlessly running a couple of benchmark/stress tests http://pic.twitter.com/fusjuyuS.

I only use my Pi on VNC over wifi, so I allocate 8mb to GPU & never have HDMI/video plugged in so I'm not sure what impact using the GPU has on temperature & general stability of an overclocked Pi.

I do have a heatsink on the Pi, which consists of an old Northbridge 40x40mm heatsink trimmed to fit, with a notch cut out for the mounting hole.

Ever since I got the Pi using raspi-config 'Turbo' mode never booted, could only do 900Mhz, so I used the config.txt file to manually change the frequencies to get 1100MHz.

Not setting the world alight, I know, just chipping in.

(1st post - whoop!! <half-hearted Tim Henman fist pump>)
512MB Revision 2 Model B Raspberry Pi, PiBow Case, Ralink nano WiFi adapter.
Raspbian Wheezy
Controlled from Mac using VNC / SSH & Bonjour (via avahi-daemon & netatalk) thanks to http://j.mp/Tno2CK

User avatar
DavidS
Posts: 4334
Joined: Thu Dec 15, 2011 6:39 am
Location: USA
Contact: Website

Re: Overclocking

Fri Jan 11, 2013 10:00 pm

Has any one attempted underclocking? Is there anyhere to find the lower liits of what can be donewith the RPi, in terms of arm_freq, sdram_freq, core_freq?

I normally run at 1GHz (1000MHz) ARM clock with 600MHz SDRAM clock and 250MHz core clock. ThoughI would like to go the other way and clock it down for testing the performence of software that I write with out having to use an emulator, or boot a RiscPC.
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

User avatar
Licaon_Kter
Posts: 240
Joined: Wed Sep 05, 2012 10:12 am
Location: Between the keyboard and the chair.

Re: Overclocking

Sat Jan 12, 2013 1:08 am

DavidS wrote:Has any one attempted underclocking? Is there anyhere to find the lower liits of what can be donewith the RPi, in terms of arm_freq, sdram_freq, core_freq?
umm nope
BFQ+BFS or RT on a RPi? 4'real: https://github.com/licaon-kter/ (source and compiled!)

User avatar
cyrano
Posts: 714
Joined: Wed Dec 05, 2012 11:48 pm
Location: Belgium

Re: Overclocking

Sat Jan 12, 2013 2:03 am

There's a thread about power consumption where someone tried it. It didn't make a significant difference in power consumption:

http://www.raspberrypi.org/phpBB3/viewt ... 0&start=25

User avatar
DavidS
Posts: 4334
Joined: Thu Dec 15, 2011 6:39 am
Location: USA
Contact: Website

Re: Overclocking

Sat Jan 12, 2013 5:32 am

I have read those other threads. Unfortunately it seems that no one is attempting to pust the lower limits to test how well there code is optimized thus far. Unless I have missed something?

I have been slowly working my way down as time allows. Though so far I have only been fiddling with arm_freq. The slowest I have got to thus far is 18MHz. That may actualy be slow enough, though I would like to see 4MHz, because 4MHz would give simular performance to the original 8MHz ARMv2 :). I am fairly certain that I will not be able to get the SDRAM under 40MHz (refresh is allways a concern).
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

User avatar
DavidS
Posts: 4334
Joined: Thu Dec 15, 2011 6:39 am
Location: USA
Contact: Website

Re: Overclocking

Sat Jan 12, 2013 5:09 pm

On the flip side:
When runing RISC OS with the fallowng added to the CONFIG.TXT:

Code: Select all

arm_freq=1000
core_freq=250
sdram_freq=600
over_voltage=6
force_turbo=1
Everything runs stable, include some very intence homebrew memory and cpu burn tests. BUT NetSurf will crash Much more often than normal. I can not figure out what NetSurf uses that is acting differently, but it crashes.
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

User avatar
DavidS
Posts: 4334
Joined: Thu Dec 15, 2011 6:39 am
Location: USA
Contact: Website

Re: Overclocking

Sat Jan 12, 2013 10:03 pm

Ok I have done some more bare metal testig, and overclocking the SDRAM to high causes strange results. With the SDRAM at 600MHz, I can reliably read and write all RAM from 0x00002000 through 0x0FFFFFFA though addresses from 0x0FFFFFFB through 0x1FFFFFFF are less reliable. I have not yet played with memory below 0x00002000 as I am in the habit o reserving this area for my hobby OS startup code and vectors.

Does anyone hae any idea as to why this may be?
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

dpeppitt
Posts: 4
Joined: Wed Feb 27, 2013 6:25 pm

Re: Overclocking

Thu Feb 28, 2013 4:04 pm

1.2GHZ cpu
350mhz gpu
500mhz ram

no heat issies just fiddle around and ule get it stable, u may need some cooling

BotenRedWolf
Posts: 5
Joined: Thu Mar 14, 2013 9:52 pm

Re: Overclocking

Mon Mar 25, 2013 2:09 pm

arm_freq=1100
core_freq=700
sdram_freq=533
over_voltage=6
force_turbo=1

Stable and never breaks 52 degrees even under full load. I've been tinkering and would like to figure out how to bring it to maybe 1.2 or 1.3GHz if it's possible. I've got a heatsink that takes up the whole center of the board and a 5V 5A supply so cooling and power availability are of no concern.

netadpt
Posts: 1
Joined: Fri Apr 05, 2013 12:21 am

Re: Overclocking

Fri Apr 05, 2013 12:31 am

Hey Dom,
What would the most ideal settings be for running OpenELEC for a media center? I am reading all this information and it seems everyone has different settings etc, so I am a bit confused. I have the 512mb rev B board.

My main goal is performance without overheating or anything. Also, I have installed 3 little heat sinks!

Thanks in advance!!!!

dom
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 5282
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge

Re: Overclocking

Fri Apr 05, 2013 12:03 pm

netadpt wrote: What would the most ideal settings be for running OpenELEC for a media center? I am reading all this information and it seems everyone has different settings etc, so I am a bit confused. I have the 512mb rev B board.
"everyone has different settings" is the key point. You are *over* clocking. If higher settings worked for everyone, they would be set as a default.

My settting are:

Code: Select all

arm_freq=1000
over_voltage=6
core_freq=500
sdram_freq=600
which is pretty high, but works on most boards I've tried. It requires a decent power supply (e.g. the USB port of my TV is not sufficient).
If you get crashes or reboots, you should wind down the settings until you find a stable point.
(Reboots may be cured with current_limit_override).

I also set:

Code: Select all

force_turbo=1
current_limit_override=0x5A000020
But these set the warranty bit.

*** I'd suggest you backup your sdcard before attempting this. Too high an overclock can result in sdcard corruption ***

OtherCrashOverride
Posts: 582
Joined: Sat Feb 02, 2013 3:25 am

Re: Overclocking

Fri Apr 05, 2013 1:26 pm

But these set the warranty bit.
How do you read the warranty bit? It would be good to know if purchasing a 2nd hand board whether it may be potentially damaged.

lokir
Posts: 3
Joined: Thu Jun 14, 2012 2:45 pm

Re: Overclocking

Fri Apr 05, 2013 2:03 pm

cat /proc/cpuinfo

Revision : 100000f

if it start with 1 your warranty in gone :)

lokir
Posts: 3
Joined: Thu Jun 14, 2012 2:45 pm

Re: Overclocking

Fri Apr 05, 2013 2:11 pm

netadpt wrote:Hey Dom,
What would the most ideal settings be for running OpenELEC for a media center? I am reading all this information and it seems everyone has different settings etc, so I am a bit confused. I have the 512mb rev B board.

My main goal is performance without overheating or anything. Also, I have installed 3 little heat sinks!

Thanks in advance!!!!
I got my

arm_freq=850
sdram_freq=500
initial_turbo=45

with RSS off and Quartz Theme. Works as a charm.

elig
Posts: 1
Joined: Sun Apr 21, 2013 12:22 am

Re: Overclocking

Sun Apr 21, 2013 12:26 am

Wanted to give my settings, notice the low overvolt:

arm_freq=950
core_freq=500
sdram_freq=500
over_voltage=2

force_turbo=0

Seems perfectly stable, but if I lower the overvolt by even 1 it won't boot. Doesn't get too hot, either. I can't increase arm_freq any more or it won't boot. I bet that I could increase the others slightly, though. They seem to be more tolerant.

Return to “Advanced users”