PanjaNL
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Joined: Sat Sep 07, 2013 6:49 pm

[Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 7:31 pm

I recently purchased a Rpi 3B+ with an official Rpi 5.1v/2.5a power supply.
I have searched and found that the 3B+ should have these default speeds:
  • CPU: 1400 MHz
    CORE: 400 MHz
    RAM: 500 MHz
    GPU: 300 MHz
Installed RetroPie and updated all packages to the latest (4.4.2).
If I run these commands:

Code: Select all

vcgencmd get_config int | grep arm_freq
vcgencmd get_config int | grep core_freq
vcgencmd get_config int | grep sdram_freq
vcgencmd get_config int | grep gpu_freq
I'm getting different speeds:
  • arm_freq=1400
    core_freq=250
    sdram_freq=450
    gpu_freq=300
Is there something wrong with my 3B+?

Source: https://www.raspberrypi.org/documentati ... locking.md


[edit]
Changed formatting
Last edited by PanjaNL on Tue Sep 04, 2018 9:41 pm, edited 5 times in total.

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DarkPlatinum
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 7:55 pm

I am not 100% sure, but doesn't the clock speed deacrease while not taxed heavily? Correct me if im wrong.
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PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 7:57 pm

As far as I know you are correct.
Though these commands should give me the max speeds and not the current (idle or decreased speeds).
So I think they are still not correct.

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DarkPlatinum
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 8:03 pm

Check your config.txt file, retropie might have a default clockspeed.
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pfletch101
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 8:17 pm

Interesting!

On my 3B+, vcgencmd gives:

Code: Select all

arm_freq=1400
core_freq=400
gpu_freq=300
sdram_freq=450
A couple of these are a bit lower than the specs you quote, but at least the arm_freq is on spec. On the one of my (fairly new) 3Bs that is currently in use, vcgencmd gives:

Code: Select all

arm_freq=1200
core_freq=400
gpu_freq=300
sdram_freq=450
Are you sure that your 3B+ isn't really an older 3B?!

PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 8:42 pm

That was the first thing that I thought of as well. But on the PCB it says:
Raspberry Pi 3 Model B+
Raspberry Pi 2017

Core speed is way off!
Also ram should be 500 MHz...

The config.txt is default.
There are no settings for over or underclocking.

MaxVMH
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 9:12 pm

Here are my results :)

Raspberry Pi 3B+, same results as pfletch101:

Code: Select all

23:05:28 up 101 days, 10:02,  1 user,  load average: 0.30, 0.27, 0.27
arm_freq=1400
core_freq=400
gpu_freq=300
sdram_freq=500


Raspberry Pi 3B:

Code: Select all

23:03:27 up 101 days, 10:00,  1 user,  load average: 0.43, 0.33, 0.29
arm_freq=1200
core_freq=400
gpu_freq=300
sdram_freq=450
Webserver stack: 2x Pi 3B | 1x Pi 3B+ ||| Pi Zero W for fooling around

Working on a soccer prediction web app:
https://github.com/MaxVMH/mijnscore
Attempt at writing up-to-date tutorials on making a Raspberry Pi webserver:
http://blog.mijnscore.be/

PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 9:17 pm

Not completely the same. Your ram speed is 500 MHz. Which should be the default.

Keeps getting stranger and stranger...

MaxVMH
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Re: [Question] Are my Rpi 3B+ speeds normal?

Tue Sep 04, 2018 9:24 pm

Yes, looks like you're right. I got a better one :lol:
Webserver stack: 2x Pi 3B | 1x Pi 3B+ ||| Pi Zero W for fooling around

Working on a soccer prediction web app:
https://github.com/MaxVMH/mijnscore
Attempt at writing up-to-date tutorials on making a Raspberry Pi webserver:
http://blog.mijnscore.be/

jamesh
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 8:57 am

Try the latest Raspbian.
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hippy
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 9:19 am

MaxVMH wrote:
Tue Sep 04, 2018 9:12 pm
Raspberry Pi 3B:

Code: Select all

23:03:27 up 101 days, 10:00,  1 user,  load average: 0.43, 0.33, 0.29
arm_freq=1200
core_freq=400
gpu_freq=300
sdram_freq=450
My quite old Pi 3B but running updated Stretch gives -

Code: Select all

arm_freq=1200
core_freq=250    <---- ?
gpu_freq=300    
sdram_freq=450
There is nothing in config.txt which sets core_freq I can see, and I am sure it's a stock install and raspi-config won't allow overclocking so can't see that I have ever overclocked or underclocked.

Then I noticed that the UART has been enabled and that's probably what has auto-adjusted the core_freq.

Perhaps that's why the OP's core_freq is also 250. I have no idea why their sdram_freq on the 3B+ is 450 not 500.
Last edited by hippy on Wed Sep 05, 2018 9:31 am, edited 1 time in total.

PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 9:28 am

hippy wrote:
Wed Sep 05, 2018 9:19 am
Then I noticed that the UART has been enabled and that's probably what has auto-adjusted the core_frequency.
Perhaps that's why your core_freq is also 250.
Indeed UART is enabled, this is done automatically by installing the safe shutdown script for the Nespi Case+
https://github.com/RetroFlag/retroflag-picase


Safe shutdown install.sh script:

Code: Select all

#Step 2) enable UART----------------------------------------
cd /boot/
File=config.txt
if grep -q "enable_uart=1" "$File";
	then
		echo "UART already enabled. Doing nothing."
	else
		echo "enable_uart=1" >> $File
		echo "UART enabled."
fi
#-----------------------------------------------------------

Tonight I will try a fresh install of RetroPie or/and Rasbian without the safe shutdown script (UART disabled that way) and report back.

hippy
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 9:39 am

PanjaNL wrote:
Wed Sep 05, 2018 9:28 am
Once I get home tonight I will try a fresh install of RetroPie or/and Rasbian without the safe shutdown script (UART disabled that way) and report back.
You might not have to do a complete reinstall, may just be able to edit config.txt.

I ran raspi-config on my 3B, disabled UART, rebooted, and my core_freq is back to the expected 400.

You should be able to use the UART and have core_freq=400 by setting force_turbo if my reading of the documentation is right -

"The Linux console can be re-enabled by adding enable_uart=1 to config.txt. This also fixes the core_freq to 250Mhz (unless force_turbo is set, when it will fixed to 400Mhz), which means that the UART baud rate stays consistent".

https://www.raspberrypi.org/documentati ... on/uart.md

I haven't read the full documentation and don't have a good understanding of what all the clocking options are or mean so have no idea what any other consequence of setting force_turbo might be.

PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 9:49 am

Thanks! I will have a go tonight.

As far as I know "force_turbo" sets the speed to full all the time.
So when the Rpi is idle normally it goes back to arm_freq=600 but with this option it stays at arm_freq=1400 all time time.

PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 3:07 pm

hippy wrote:
Wed Sep 05, 2018 9:39 am
PanjaNL wrote:
Wed Sep 05, 2018 9:28 am
Once I get home tonight I will try a fresh install of RetroPie or/and Rasbian without the safe shutdown script (UART disabled that way) and report back.
You might not have to do a complete reinstall, may just be able to edit config.txt.

I ran raspi-config on my 3B, disabled UART, rebooted, and my core_freq is back to the expected 400.
Confirmed!
If I remove the "enable_uart=1" line in my /boot/config.txt the core_freq is back to 400.

The strange thing is that the shutdown and reset button on the Nespi Case+ keep on working, even when I remov the "enable_uart=1" line in my /boot/config.txt

So now I'm wondering why do I need UART enabled anyways?

ejolson
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 5:14 pm

PanjaNL wrote:
Wed Sep 05, 2018 3:07 pm
hippy wrote:
Wed Sep 05, 2018 9:39 am
PanjaNL wrote:
Wed Sep 05, 2018 9:28 am
Once I get home tonight I will try a fresh install of RetroPie or/and Rasbian without the safe shutdown script (UART disabled that way) and report back.
You might not have to do a complete reinstall, may just be able to edit config.txt.

I ran raspi-config on my 3B, disabled UART, rebooted, and my core_freq is back to the expected 400.
Confirmed!
If I remove the "enable_uart=1" line in my /boot/config.txt the core_freq is back to 400.

The strange thing is that the shutdown and reset button on the Nespi Case+ keep on working, even when I remov the "enable_uart=1" line in my /boot/config.txt

So now I'm wondering why do I need UART enabled anyways?
While 250 is smaller than 400, does the core frequency affect anything other than the serial ports?

PanjaNL
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 6:32 pm

Copy/paste from the Rpi documentation site:


core_freq
Frequency of the GPU processor core in MHz. It has an impact on CPU performance because it drives the L2 cache and memory bus. The default value is 250 for the Pi 1/Pi 2 and 400 for the Pi 3 and Pi Zero and Pi Zero W. Note that the L2 cache benefits only the Pi Zero/Pi Zero W and Pi 1, but there is a small benefit for SDRAM on the Pi 2/Pi.

hippy
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 6:50 pm

PanjaNL wrote:
Wed Sep 05, 2018 6:32 pm
there is a small benefit for SDRAM on the Pi 2/Pi.
It would be nice to have that "small" quantified in some meaningful way.

PanjaNL
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Joined: Sat Sep 07, 2013 6:49 pm

Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 7:49 pm

Still don’t have a clue why I need UART enabled...

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bensimmo
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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 8:30 pm

The ram speed was dropped (along with a timing setting) and so should not be 500 anymore, it was found some where unstable at that speed.
These are set at boot up in 'firmware' (and overridden in config.txt ) if I have that right.

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Re: [Question] Are my Rpi 3B+ speeds normal?

Wed Sep 05, 2018 8:33 pm

bensimmo wrote:
Wed Sep 05, 2018 8:30 pm
The ram speed was dropped (along with a timing setting) and so should not be 500 anymore, it was found some where unstable at that speed.
These are set at boot up in 'firmware' (and overridden in config.txt ) if I have that right.
So before reading your comment i had clocked it at 500, should i decrease it back to what value now? Is 400mhz ok?
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bensimmo
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Re: [Question] Are my Rpi 3B+ speeds normal?

Thu Sep 06, 2018 6:01 am

If you're forcing it to 500 and it doesn't crash after being left on for a day or two, leave it at 500.
I believe most (if not all but a small batch) should run at 500.

500 was the speed it was released at originally.
(Find a thread from around the first few weeks from launch day about the Pi3B+ crashing, they did a lot of diagnosis from people with the problem).

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bensimmo
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Re: [Question] Are my Rpi 3B+ speeds normal?

Thu Sep 06, 2018 6:14 am

hippy wrote:
Wed Sep 05, 2018 6:50 pm
PanjaNL wrote:
Wed Sep 05, 2018 6:32 pm
there is a small benefit for SDRAM on the Pi 2/Pi.
It would be nice to have that "small" quantified in some meaningful way.
I assume w.r.t. Pi1 being large.
From a recent thread, the Pi2&3 have onboard cache for the ARM and do not use the L2 cache, hence why it isn't a problem for them.
Also the Pi1's and Zero and Pi2 should not see the problem with Serial (gpio UART) as they don't need it since they don't use the miniUART. I assume that setting is not set when Serial Port is enabled (?) for them.
Only the WiFI/BT Pi (W and 3's ) will see the problem, of course the slowest one is hit the hardest, though I don't think it's ever been a problem for my usage.

One for the benchmarkers to have a play with ;-)

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