Overclocking

[dom]

is it possible to have overvoltage over 8 (eg. over 1.4V) or is this somehow hardcoded limit in hardware ?

A hardware limit.

[make/install]

That would be perfectly explained by a power supply that gives up at that level.

thanks. I'll try another power supply. Currently I have noname 1A supply, how much amperes you can recommend for overclocking?

[dom]

That would be perfectly explained by a power supply that gives up at that level.

thanks. I'll try another power supply. Currently I have noname 1A supply, how much amperes you can recommend for overclocking?

Unfortunately it's not that simple. A lot of cheap chargers may claim 1A or 2A, but the voltage dips when a significant amount of current is drawn.
This may just be transcient, so it can be hard to detect without a scope (although sometimes it is blatant and can be detected with a voltmeter).

I've had success with (genuine) Apple chargers, and also the Amazon Raspberry Pi power supply.

Be aware that a cheap USB power lead can also contribute to voltage drop.

[make/install]

yep. I made voltage measurement between TP1 and TP2 and it shows me only 4.4V - not enough for successful overclocking

[dom]

yep. I made voltage measurement between TP1 and TP2 and it shows me only 4.4V - not enough for successful overclocking

Yes, no need for a scope there...

[fernandovg]

This is my settings:

Code: Select all

hdmi_force_hotplug=1
hdmi_mode=32
arm_freq=1050
core_freq=500
sdram_freq=450
over_voltage=6
disable_overscan=0
gpu_mem=150
start_file=start_x.elf
fixup_file=fixup_x.dat

Using Raspbmc. With a HDD for media - everything powered by d-link hub usb. sd-card 10 class samsung. No corruption so far.
I chanded my gpu_mem because I'm running raspbmc(xmbc) with nzbget + SB + CP + deluge and I used to run out of gpu mem (1080p videos). subtitles changed to yellow blocks instead of characters and sometimes appear ok but with black background. With this gpu_mem so far no problems.

How far can I go with overclock? Can I increase 10% - to 1155?
1050 = increase 50% of 700
What would be the other values?

Any recommendations?
thanks!

[MaxK1]

Maybe - every Pi is "different" so _any_ overclocking should be considered a bonus. That said, I have 3 that overclocked to 1140 without much trouble. (I have 2 more that I haven't even tried yet). I have seen one guy report he is running at >1200 with no trouble.

[portets]

I'm running at 1225 with an over_voltage of 8. I could probably go higher if my power supply was better; it only reads 4.76 volts.
With 6 as my overvolt, I can hit 1150.

To enable over_voltage greater than 6 you need to do force_turbo=1, but this voids the warranty. You'll also probably need to do current_limit_override=0x5A000020, unless you're running the latest firmware via rpi-update, which enables current_limit_override by default.

I also see you have sdram_freq=450. If you have samsung ram(don't know about the others) you can most likely increase it to 600 without any ram overvolting.

[XBMCantgetenough]

here are my settings

arm_freq=1130
core_freq=560
h264_freq=420
isp_freq=420
v3d_freq=420
avoid_pwm_pll=1
current_limit_override=0x5A000020
sdram_freq=710
over_voltage_sdram=8
over_voltage=8
gpu_mem_512=128
initial_turbo=59
hdmi_ignore_cec_init=1
hdmi_ignore_cec=1
initial_turbo=1
init_uart_clock=4000000
init_emmc_clock=500000000
disable_pvt=1
force_turbo=1

Now I have a two questions
1/ I had my Pi running at 700 core, but vcgencmd measure_clock core only outputted 500. I went back to 500 and I really can't tell if it actually made a difference, Dom said it can only go up to 500 which is not the case because I decided to increase by 10 intervals and it went up to 600 but on my Pi its only stable at 560 so I left it. So that got me to believe vcgencmd gives out the correct output.

Now with vertical blank sync disabled on openelec I get roughly 90 frames a second goes between 90-95) I messed around with h264 and put it to 100, keeping v3d,isp to 420. Now when I ran "vcgencmd measure_clock core" I got 420 (even though I asked for 100). So did v3d/isp. But on my xbmc I got 84 frames a second. So therefore I'm not sure if vcgencmd is 100% accurate and if I put 700 for core, would it make a difference.

Dom I would love to hear your thoughts on this. Is vcgencmd accurate and can core go past 600. Its funny because with the core being at 700 it was fine but when I went like 720 it woudn't boot so whats happening? And also if I set my core at say 580 then it shows in vcgencmd thats its at 580 and it crashes after a while so then Its correct that setting at 580 is actually higher than setting it at 700 and looking at the framerate its correct I get higher frame rates at 560 than 700. But then what happened with the h264 and vcgencmd

[hojnikb]

thats a massive OC on the ram dude
Is it stable though ?

[a9971256]

I get ~700 BMIPS at 1500MHz arm 550MHz GPU and 550 CORE/SDRAM

[wallarug]

I get ~700 BMIPS at 1500MHz arm 550MHz GPU and 550 CORE/SDRAM

Have you actually gotten your Pi up to 1500 MHz?

[a9971256]

I get ~700 BMIPS at 1500MHz arm 550MHz GPU and 550 CORE/SDRAM

Have you actually gotten your Pi up to 1500 MHz?

Yes, and it is very stable under the newest wheezy distro. However, it crashes while booting with berryboot installed

[RobHenry]

I get ~700 BMIPS at 1500MHz arm 550MHz GPU and 550 CORE/SDRAM

Have you actually gotten your Pi up to 1500 MHz?

Yes, and it is very stable under the newest wheezy distro. However, it crashes while booting with berryboot installed

I find this incredulous. Either your config.txt entry is being ignored or the device is never being pushed to full load. Or you have a uniquely powerful device.

Can you post any evidence of this phenomenon?

[a9971256]

I used raspi-config to set overclock to turbo. Then I started editing arm_freq
btw, how do i post config.txt. .txt isnt allowed

[a9971256]

i cant use my pi w/o a fan

[hojnikb]

you're either trolling or have and incredible piece of silicon.

There is no way that you can run that thing at 1500Mhz, unless its not actually running that fast (due to cpufreq driver or the Pi ignores the value)

Nobody hasn't even reached 1300Mhz, let alone 1500Mhz... This would kind of feat would requre some serious handpicking and some low temparatures.. And overvoltage way beyond 1.4V...

[portets]

They said they put it in turbo mode with raspi-config, but then increased arm_freq manually. Which means their over_voltage=6. 6 is not enough to sustain such a high overclock. 6 can't even bring a normal Pi above ~1150. 8 will bring top tier Pi's to ~1300. I think their Pi isn't getting triggered to up-clock. One thing that lends some credence is that they said only the latest wheezy will boot, and if IIRC, the latest wheezy now contains the current limit override by default.

Hey a9971256, if you're okay with voiding your warranty, set "force_turbo=1".

[dom]

I used raspi-config to set overclock to turbo. Then I started editing arm_freq
btw, how do i post config.txt. .txt isnt allowed

Run

Code: Select all

vcgencmd measure_clock arm

and post output.

[dom]

Dom I would love to hear your thoughts on this. Is vcgencmd accurate and can core go past 600. Its funny because with the core being at 700 it was fine but when I went like 720 it woudn't boot so whats happening? And also if I set my core at say 580 then it shows in vcgencmd thats its at 580 and it crashes after a while so then Its correct that setting at 580 is actually higher than setting it at 700 and looking at the framerate its correct I get higher frame rates at 560 than 700. But then what happened with the h264 and vcgencmd

vcgencmd measure_clock is definitive. It runs a counter off the clock for a fixed period of time.
All the clocks have a ceiling (normally related to PLL's ceiling of 2.4GHz). You should see that through measure_clock if you get that high.

[XBMCantgetenough]

thats a massive OC on the ram dude
Is it stable though ?

Yes its stable in the sense that I can run it for hours without problem them when after it starts to reboot every half an hour but this leads me to think its the combined effect of heat and also I've heard that reboots are caused by drop in voltage (I'm running charger for nexus 4) And I can tell you its lightning. I'm getting 90 frames per second, it won't go below that. The reason why I get so high Ram is because I've got overvolatge_sdram at 8 (my post said 7, its unstable at that voltage and the its actually 8 that works good) which no one has tried to go that high but it works and I I've ran measure_voltage and get the correct 1.4 volts. But saying that theres no command to check the sdram.

Dude try it out yourself. I'm confident Pi's can reach 650 sdram with an overvoltage. make sure you do disable_pvt=1 (Disable adjusting the refresh rate of RAM every 500ms (measuring RAM temparature)) I think this helps.And I'm jelous you can reach arm at 1225 I can't get past 1150 and even at that its unstable and crashes. Even if I reduce everything else to default values

BTW i'm running of USB install on Openelec. I don't think you can achieve it on sd card

[XBMCantgetenough]

Dom one thing I have picked up on that no I've not read on any forum is that with avoid_pwm_pll=1 you can't set isp/vd3/h264 at independent values they won't budge, they see whats the highest value you've picked up for any GPU pll's and choose that for all of them. Except I remeber I picked one value for Isp and it stuck on that but I can't seem to repeat that result. I'm interested to setting Isp=0 with v3d/h264=420 because I'm only using XBMC. Any thoughts Dom?

[a9971256]

my config.txt

Code: Select all

core_freq=550
sdram_freq=550
gpu_freq=550
arm_freq=1400
over_voltage=6
# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# for more options see http://elinux.org/RPi_config.txt

[XBMCantgetenough]

my config.txt

Code: Select all

core_freq=550
sdram_freq=550
gpu_freq=550
arm_freq=1400
over_voltage=6
# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# for more options see http://elinux.org/RPi_config.txt

No way! GPU frequencies and Arm run off the overvolatge and to get 550!!GPU and 1400!!Arm from a paltry 6 over volts (1.35 volts). You should be atleast using current_limit_override=0x5A000020. Its either a troll or I'm impressed. Are you running of a USB3?

I find it amusing some wanting or claiming to get a high over clock with such perfect rounded off numbers as 1400, Why not 1410 or 1395? abit suspicious, because anyone seriously trying to squeeze as much juice out as possible will know to at least go by 5 intervals until you reached the peak before it becomes unstable? Anyone else think the same?

[wallarug]

No way! GPU frequencies and Arm run off the overvolatge and to get 550!!GPU and 1400!!Arm from a paltry 6 over volts (1.35 volts). You should be atleast using current_limit_override=0x5A000020. Its either a troll or I'm impressed. Are you running of a USB3?

I find it amusing some wanting or claiming to get a high over clock with such perfect rounded off numbers as 1400, Why not 1410 or 1395? abit suspicious, because anyone seriously trying to squeeze as much juice out as possible will know to at least go by 5 intervals until you reached the peak before it becomes unstable? Anyone else think the same?

I have to agree with you here. It is almost impossible to get that sort of clock out of the ARM. It would probably burn itself out due to the over-voltage required out before reaching that speed.

On the other hand: If he/she as achieved this, they should be able to show some evidence, such as picture of the Pi taking some load and then showing the freq. In addition to this, it would also be nice to know what board he/she owns and done this on.