RyuX
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Re: Overclocking

Tue Jan 13, 2015 1:33 am

Hey guys, any ways of doing the voltmod on a Raspberry Pi B+ ?

Thanks

ktb
Posts: 1380
Joined: Fri Dec 26, 2014 7:53 pm

Re: Overclocking

Wed Jan 14, 2015 6:07 am

I'll share the config that has been working well for me on my B+ running Raspbian. I have heatsinks and a fan.

Code: Select all

# I used to run it at 1100, but It's been fairly stable at 1200 for days so far
arm_freq=1200
core_freq=525
gpu_freq=525
h264_freq=525
isp_freq=525
v3d_freq=525
sdram_freq=525

over_voltage=11
over_voltage_min=7
over_voltage_sdram=8
over_voltage_sdram_c=0
over_voltage_sdram_i=0
over_voltage_sdram_p=0

disable_l2cache=0
force_turbo=1
temp_limit=83
#avoid_pwm_pll=1
current_limit_override=0x5A000020

gpu_mem=128

SirionRazzer
Posts: 1
Joined: Mon Jan 19, 2015 8:50 pm

Re: Overclocking

Mon Jan 19, 2015 9:02 pm

I´have chosen Turbo mode before, but due to lack of speed I changed arm_freq from previous 1000 to 1150. Does this mean the warranty is voided? I didn´t change anything else. I have read a bit about overclocking and overvolting, but I´ve tried onlu preset modes and the one above. Thanks, sorry for my poor English ;)

Current setting from config.txt:
arm_freq=1150
core_freq=500
sdram_freq=600
over_voltage=6

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expandables
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Re: Overclocking

Mon Jan 19, 2015 9:48 pm

Can all b+ pi's reach to arm_freq=1100?
By thinking like an engineer you can create a raspberry pi.
Michael Jackson enthusiast.
I got the PI model B, B+ and PI 2 model B.
When will I get the A? I don't know.

DirkS
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Location: Essex, UK

Re: Overclocking

Mon Jan 19, 2015 9:49 pm

expandables wrote:Can all b+ pi's reach to arm_freq=1100?
no

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expandables
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Re: Overclocking

Sat Jan 31, 2015 6:14 pm

Is there a script to test to see if a raspberry pi is stable using a specific overclock setting if so can you share thanks.
By thinking like an engineer you can create a raspberry pi.
Michael Jackson enthusiast.
I got the PI model B, B+ and PI 2 model B.
When will I get the A? I don't know.

ktb
Posts: 1380
Joined: Fri Dec 26, 2014 7:53 pm

Re: Overclocking

Sat Jan 31, 2015 6:47 pm

expandables wrote:Is there a script to test to see if a raspberry pi is stable using a specific overclock setting if so can you share thanks.
http://elinux.org/RPiconfig#Overclock_stability_test

dom
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Location: Cambridge

Re: Overclocking

Sat Jan 31, 2015 6:51 pm

To be honest that's not really going to stress the chip. You'd be much better running quake or kodi.

I do have a much better stress test, with a script that will identify the highest arm_freq, core_freq and sdram_freq that are reliable for your particular board.
Still needs a bit more testing, but I'm hoping to make it available in the next week or two.

ktb
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Re: Overclocking

Sat Jan 31, 2015 6:57 pm

dom wrote:
To be honest that's not really going to stress the chip. You'd be much better running quake or kodi.

I do have a much better stress test, with a script that will identify the highest arm_freq, core_freq and sdram_freq that are reliable for your particular board.
Still needs a bit more testing, but I'm hoping to make it available in the next week or two.
Very cool. My "test" is whether or not the Pi can successfully boot and compile kernels/packages.

I'd be happy to abuse my B+ with your script if you want any testers.

PuppetHoundZ
Posts: 170
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Re: Overclocking

Wed Feb 04, 2015 10:49 pm

I've done a lot of reading on this subject and I'm not willing to tinker too much with the fear of having to deal with SD Card corruption. I'm mostly interested a overall overclock that seems to just work on all Pis regardless of how much faster it can actually go.

What is that overclock that Raspbmc uses by default and should I use that for my default care free overclock in Raspbian?

Overall, is the most modest setting a fairly trouble free stable over clock (800mhz) is it that one Raspbmc uses?

I just want it to get a small boast without trouble shooting fyi :D


Update:
dom wrote: I do have a much better stress test, with a script that will identify the highest arm_freq, core_freq and sdram_freq that are reliable for your particular board.
Still needs a bit more testing, but I'm hoping to make it available in the next week or two.
Now this is somthing I would be interested in :geek:

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Lob0426
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Re: Overclocking

Wed Feb 04, 2015 11:05 pm

The 850MHz settings should be good on just about every RasPi out there. It works on all of mine.
512MB version 2.0 as WordPress Server
Motorola Lapdock with Pi2B
Modded Rev 1.0 with pin headers at USB

http://rich1.dyndns.tv/
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PuppetHoundZ
Posts: 170
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Re: Overclocking

Wed Feb 04, 2015 11:22 pm

@ Lob0426
Is that Raspbmc uses or is that higher or from your overall experience with just standard no trouble shooting setup?

update:
Also what ram allocation do you recommend for like desktop and multi media use (ie using Pi for Browser and Games and youtube using Epiphany)? I read up 240mb GPU was good or do you use something else?

Update I'm look up this post for maybe a better way to be more sure if I can actually overclock my Pi:
http://www.raspberrypi.org/forums/viewt ... 78#p582078

Looks like I'm getting into this so maybe I can go beyond the basic over clock setting of 800mhz but to be safe in all regards I'm going to try the above post.

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Lob0426
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Re: Overclocking

Thu Feb 05, 2015 1:17 am

I found it to be stable on all my RasPii. In quake, OpenElec and Raspbian.
Raspi-config settings of modest to medium work on all but one of my boards. 850MHz is between those. None of mine like Turbo, Model B rev1.0 and 2.0 boards. The B+ is Ok at medium (900MHz).

I do not push above the Medium setting.

Every board is different and needs to be stability tested. But Modest to Medium seem to work on the majority!
512MB version 2.0 as WordPress Server
Motorola Lapdock with Pi2B
Modded Rev 1.0 with pin headers at USB

http://rich1.dyndns.tv/
(RS)Allied ships old stock to reward its Customers for long wait!

PuppetHoundZ
Posts: 170
Joined: Wed Jan 21, 2015 2:57 am

Re: Overclocking

Thu Feb 05, 2015 1:43 am

Lob0426 wrote:I found it to be stable on all my RasPii. In quake, OpenElec and Raspbian.
Raspi-config settings of modest to medium work on all but one of my boards. 850MHz is between those. None of mine like Turbo, Model B rev1.0 and 2.0 boards. The B+ is Ok at medium (900MHz).

I do not push above the Medium setting.

Every board is different and needs to be stability tested. But Modest to Medium seem to work on the majority!
I found out with the below number to be the average:

Code: Select all

vcgencmd read_ring osc
3.098MHz (1.2000V)
http://www.raspberrypi.org/forums/viewt ... 28#p684928

Which means I can do turbo mode then? (update I guess I can :geek: )

Update: Yeah I read the forum post! It works in turbo mode with Epiphany playing video in 720p within browser with minimal stuttering! (but stutters a bit when in full screen but doesn't ever crash ;) )

My temperature is around +/- :

Code: Select all

temp=54.1'C
Is that good or bad (hope not)?

Update: This is unbelievable! I can't believe I can overclock my Pi like this still running solid after 30+ mins of watching 720p video on epiphany with 97% cpu usage!

PS: Is Epiphany a playing video a good way to test Overclocking Stability!? (hope so)

Update: I tested Turbo mode with Prboom and it ran fine: it was getting 53.0'C and was using 100% ARM (1000) and Core (500) for a long time and didn't crash. Changing the resolution settings on PRboom to 1080p and running it without X causes the 8 Act LED crash one time and other times it totally freezes the Pi. I think it's PrBoom bug but I'll be testing it with default tonight.

Update: It also prints using CUPS in epiphany browser! It printed and the Pi didn't freeze up my like it used to when running default clock. I find it weird that the Pi in turbo mode will run certain apps more stable then it did in default clock settings. I'll be updating with Prboom issue in a few hours. One more try and I'll know for sure that its PRboom or Overclock causing the crash.

Update: It's a PRBoom Issue maybe as a result of the new Kernel or a library update as it does the same crashes default or turbo. Always run that in X I guess.

So everything seems to run more stable on Turbo than Default especially printing, Epiphany browser playing video and games. No apparent crashing other than typical software bugs. This is epic.
Last edited by PuppetHoundZ on Fri Feb 06, 2015 2:35 am, edited 4 times in total.

ktb
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Re: Overclocking

Thu Feb 05, 2015 7:57 am

With the Raspberry Pi 2 Model B, it doesn't seem like I'm able to affect/tweak the GPU (h264, isp, v3d) clocks directly any longer or maybe the relationships of some of the clocks no longer behaves as on the B+. No matter what I do, I can't get seem to get those clocks over 250000000.

Maybe this is a power issue. I don't know. I'm using a 2A supply from a Samsung tablet that works fine to power my B+ @1200MHz. I have noticed the little rainbow square show up only momentarily on boot and then fade away which doesn't happen on my B+.

PuppetHoundZ
Posts: 170
Joined: Wed Jan 21, 2015 2:57 am

Re: Overclocking

Thu Feb 05, 2015 8:37 am

ktb wrote:With the Raspberry Pi 2 Model B, it doesn't seem like I'm able to affect/tweak the GPU (h264, isp, v3d) clocks directly any longer or maybe the relationships of some of the clocks no longer behaves as on the B+. No matter what I do, I can't get seem to get those clocks over 250000000.

Maybe this is a power issue. I don't know. I'm using a 2A supply from a Samsung tablet that works fine to power my B+ @1200MHz. I have noticed the little rainbow square show up only momentarily on boot and then fade away which doesn't happen on my B+.
Any rainbow of any kind means power issue!

B+ doesn't use as much power as B. So I wouldn't recomend overclocking that until you sort out the Power issues first. I had power issues myself until I got a better USB Cable. The Samsung Chargers are great! You're USB cable needs to be better. Search for a Monoprice Micro-USB cable on Amazon that solved all my power issues.

ktb
Posts: 1380
Joined: Fri Dec 26, 2014 7:53 pm

Re: Overclocking

Thu Feb 05, 2015 8:46 am

PuppetHoundZ wrote:
ktb wrote:With the Raspberry Pi 2 Model B, it doesn't seem like I'm able to affect/tweak the GPU (h264, isp, v3d) clocks directly any longer or maybe the relationships of some of the clocks no longer behaves as on the B+. No matter what I do, I can't get seem to get those clocks over 250000000.

Maybe this is a power issue. I don't know. I'm using a 2A supply from a Samsung tablet that works fine to power my B+ @1200MHz. I have noticed the little rainbow square show up only momentarily on boot and then fade away which doesn't happen on my B+.
Any rainbow of any kind means power issue!

B+ doesn't use as much power as B. So I wouldn't recomend overclocking that until you sort out the Power issues first. I had power issues myself until I got a better USB Cable. The Samsung Chargers are great! You're USB cable needs to be better. Search for a Monoprice Micro-USB cable on Amazon that solved all my power issues.
I appreciate the thought, but I don't think it's the cable. I can and will try a couple of other cables. The one I usually rely on is 26AWG. I don't think that is the problem.

Will somebody please confirm the test points on the Pi2B are the same as the B+? PP3 (GND) and PP7 (VCC)?

PuppetHoundZ
Posts: 170
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Re: Overclocking

Thu Feb 05, 2015 5:55 pm

ktb wrote:

Will somebody please confirm the test points on the Pi2B are the same as the B+? PP3 (GND) and PP7 (VCC)?
It's been know that the new kernel doesn't like overclocking in some cases. Btw, you didn't mention you were using Pi2B you just said B. The original PiB was very power hungry which is why I said that that.The New Pi2B uses less power than PiB but more than PiB+. hope that makes sense. :D

Updated. Sorry but it's Power issue. Please find a related topic please since you're off topic now try this sticky (read-only):
http://www.raspberrypi.org/forums/viewt ... 28&t=58151
Last edited by PuppetHoundZ on Thu Feb 05, 2015 8:27 pm, edited 1 time in total.

ktb
Posts: 1380
Joined: Fri Dec 26, 2014 7:53 pm

Re: Overclocking

Thu Feb 05, 2015 6:06 pm

PuppetHoundZ wrote:
ktb wrote:

Will somebody please confirm the test points on the Pi2B are the same as the B+? PP3 (GND) and PP7 (VCC)?
It's been know that the new kernel doesn't like overclocking in some cases. Btw, you didn't mention you were using Pi2B you just said B. The original PiB was very power hungry which is why I said that that. The New Pi2B uses less power than PiB but more than PiB+. hope that makes sense. :D
I'm pretty sure I wrote "Raspberry Pi 2 Model B."

In any case, the small square shows up momentarily on boot whether overclocked/overvolted or not.

Thanks.

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jackjt8
Posts: 31
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Re: Overclocking

Thu Feb 05, 2015 10:54 pm

Dan Froberg wrote: Remove the inductor L5.
Question being what is the 'recommended' way of doing so? I don't really want to nuke my board with too much heat. I assume it's not as easy as removing the etho or USB ports...
Beep Boop

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jackjt8
Posts: 31
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Re: Overclocking

Thu Feb 19, 2015 5:24 pm

Ok, removing inductor L5 was easier than I thought. The hard part was getting the wire from RG1(mid) to C16(far)... (I'm not very good at soldering)

The best part is my Pi booted up just fine after the mod.. However, when checking the in the voltage using

Code: Select all

vcgencmd measure_volts core
I get volt=1.20V. So part of me is thinking my soldering from RG1 to C16 wasn't very good... So either way, I tried applying an OC in the config which didn't work.. Well, put simply, I'm hitting a kernal panic anytime I try and boot the Pi now. Regardless of whether or not I have an OC or equivalent.

Anyone have any ideas?

---

I forgot to set avoid_pwm_pll=1 ... Guessing that did it?
Beep Boop

hglm
Posts: 30
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Re: Overclocking

Fri Feb 20, 2015 4:18 pm

ktb wrote:With the Raspberry Pi 2 Model B, it doesn't seem like I'm able to affect/tweak the GPU (h264, isp, v3d) clocks directly any longer or maybe the relationships of some of the clocks no longer behaves as on the B+. No matter what I do, I can't get seem to get those clocks over 250000000.
The "core_freq" setting in config.txt seems to have quite a different meaning on the Raspberry Pi 2. This does not (yet) appear to be clearly documented.

The original Raspberry Pi models do not really have L2 CPU cache, so "core_freq" sets the frequency of the L2 cache of the GPU. I think that as a side effect, this may also change the clock frequency of GPU blocks because their is a relationship between the two frequencies. So when increasing the "core_freq" to say 500 MHz on the Raspberry Pi, it actually also increases GPU speed.

However, the Raspberry Pi 2 actually has a separate L2 CPU cache of 512 KB, which is a great help for performance. This is what "core_freq" seems to refer to with the Pi 2; the core_freq settings now sets the L2 CPU cache speed and has little to do with the GPU, a very different meaning when compared to the Raspberry Pi.

On the Raspberry Pi 2, the "core_freq" settings (the L2 CPU cache speed) seems to default to 250 MHz which appears to be extremely conservative, since speeds up to 600 MHz appear to be stable on my Raspberry Pi 2. Increasing the L2 CPU cache speed with "core_freq" has a noticeable effect on performance, especially memory performance (with the default setting, certain metrics, such as memset performance, are actually lower than the original non-overclocked RPi).

The raspi-config utility still lacks a sensible default settings for the Raspberry Pi 2, and the standard "Pi 2" overclock (1000 MHz CPU, 500 MHz "core_freq" (L2 CPU cache), and 500 MHz SDRAM is unstable on my device because the SDRAM speed is too high. However, decreasing SDRAM frequency to 483 MHz does the trick and seems to result in total stability, with very good performance. I do not have to increase any of the voltages. Example config.txt settings:

Code: Select all

arm_freq=1000
over_voltage=0
core_freq=500
sdram_freq=483
over_voltage_sdram_p=0
over_voltage_sdram_i=0
over_voltage_sdram_c=0
Overclocking the GPU on the Raspberry Pi 2 seems to require the use of the "force_turbo=1" setting which may void the warranty. When I tried this, I was able to overclock the V3D core (3D graphics) all the way to 450 MHz without encountering stability issues, although saw the little rainbow square pop up in the corner with a reduction in fps in some benchmarks. "force_turbo=1" has the significant drawback of locking the CPU and L2 cache at the highest possible speed, so it is far from ideal (I tested it with the default CPU speed of 900 MHz). Example setttings:

Code: Select all

force_turbo=1
avoid_pwm_pll=1
v3d_freq=350
In fact, because the SoC in the Raspberry Pi 2 seems to have largely independent clock frequencies for the different cores (CPU, L2 cache, GPU parts), I think these limitations are no longer necessary and it should be possible to change the GPU clock frequencies at the same time as using the default dynamic clock frequency mechanism for CPU and L2 cache.

I have done a write-up on my overclocking experience with the Raspberry Pi 2 in a blog article (http://linuxonflash.blogspot.com/2015/0 ... mance.html).

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hojnikb
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Location: @Home

Re: Overclocking

Fri Feb 20, 2015 4:31 pm

dom wrote:
To be honest that's not really going to stress the chip. You'd be much better running quake or kodi.

I do have a much better stress test, with a script that will identify the highest arm_freq, core_freq and sdram_freq that are reliable for your particular board.
Still needs a bit more testing, but I'm hoping to make it available in the next week or two.
Any word on this script yet ?
+°´°+,¸¸,+°´°~ Everyone should have a taste of UK Raspberry Pie =D ~°´°+,¸¸,+°´°+
Rasberry Pi, SoC @ 1225Mhz :o, 256MB Ram @ 550Mhz, 16GB SD-Card, Raspbian

gregs
Posts: 1
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Re: Overclocking

Mon Mar 09, 2015 11:21 pm

hglm wrote:However, decreasing SDRAM frequency to 483 MHz does the trick and seems to result in total stability, with very good performance. I do not have to increase any of the voltages.
[...]
I have done a write-up on my overclocking experience with the Raspberry Pi 2 in a blog article (http://linuxonflash.blogspot.com/2015/0 ... mance.html).
I found your write-up very helpful and have had good success with the 1100+4/550/483 setting shown at the top of your table of stable high-performance clock configurations.
A few questions:
  • I noticed your settings seem to go up in 16.667MHz steps (450/467/483/500). Is there any particular reason for this instead 10, 15, 20, or 25MHz? Does it matter that the pi uses a 19.2MHz crystal?
  • You show a CPU:Core column where most of the stable configs are close to 2:1 or 3:2. I understand that CPU and RAM speeds are usually kept at ratios like this. Does it matter if the CPU:SDRAM ratio is not even? What are the implications of setting the SDRAM to 483MHz?
  • Would it be possible to set it to something closer to 1200/600/600? What settings would you use?

hglm
Posts: 30
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Re: Overclocking

Tue Mar 10, 2015 3:11 pm

gregs wrote: I found your write-up very helpful and have had good success with the 1100+4/550/483 setting shown at the top of your table of stable high-performance clock configurations.
A few questions:
  • I noticed your settings seem to go up in 16.667MHz steps (450/467/483/500). Is there any particular reason for this instead 10, 15, 20, or 25MHz? Does it matter that the pi uses a 19.2MHz crystal?
  • You show a CPU:Core column where most of the stable configs are close to 2:1 or 3:2. I understand that CPU and RAM speeds are usually kept at ratios like this. Does it matter if the CPU:SDRAM ratio is not even? What are the implications of setting the SDRAM to 483MHz?
  • Would it be possible to set it to something closer to 1200/600/600? What settings would you use?
It is probably not strictly necessary to use 16.667 MHz steps for the DRAM speed, but I don't know what the precision of the programmable DRAM clock actually is. When you specify a DRAM speed of say 490 MHz, it is very possible that it will be rounded to the nearest speed that can be set, which could be 483 MHz but it is also possible that 490 MHz can be set fairly accurately. The speed of the crystal on the circuit board does not say everything because it is the internal PLL circuitry inside the SoC chip that determines the actual clock speeds of the different hardware components. Their may be a command to read back the actual frequencies used from a running device.

From my experience with ARM Cortex-based devices, the DRAM frequency does not need to be be a simple fraction of the core (L2 cache) or CPU frequency. The SoC probably has a flexible interface between the CPU/L2-cache and the DRAM controller can handle a variety of DRAM speeds. In the case of the original Raspberry Pi, this may not be the case as it was noted that certain DRAM speeds are more stable when overclocking (in fact I believe the DRAM speed for the Turbo overclock was set to 600 MHz specifically because 500 MHz was not stable in the long run when used with a CPU frequency of 1.0 GHz and a core frequency of 500 MHz).

The exact DRAM speed may also influence (memory) performance, and a simple fraction-relationship between the CPU/L2 and the DRAM controller speed may or may not increase performance. From looking at the CPU benchmarks I performed the configurations with a 2:1 CPU:Core (L2 cache) ratio seemed to have a performance advantage, but the DRAM speed may not matter too much.

Some Raspberry Pi 2 SoCs can probably handle 1200/600 in terms of CPU and L2 cache frequency, but since the LPDDR2-SDRAM chips used on the Raspberry Pi 2 are only specified for 400 MHz (at least on my device) it is unlikely that a memory speed of 600 MHz speed will be possible. The situation is different for the original Raspberry Pi models because they use faster RAM chips that are embedded on the chip package of the SoC and can handle memory speeds up to 600 MHz.

When trying 1200/600 for CPU/core (L2 cache) frequency I would keep the DRAM frequency conservative to start with (like the 450 MHz I used in my test). An "over_voltage" setting for the CPU/core is probably necessary (for example, "over_voltage=6") which is within the range allowed by default.

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