How to Overclock the Pi Mk 3

Let’s be quite clear about this, I came across this by chance rather than any deep Pi understanding.

Just in case it helped I tried the current firmware on the Raspberry Pi Mk3.

bootcode.bin  01Feb16
fixup.dat     04Mar16
start.elf     04Mar16

The small multicoloured square appeared permanantly at the top right of the screen. That AIUI indicates under voltage. The power supply is the new 2A Universal Raspberry Pi Power Supply. The square persists when powered from a PiHub and from another 2A supply. The previous firmware does not do this.

bootcode.bin  01Feb16
fixup.dat     25Feb16
start.elf     29Feb16

The RPi2 is good with the latest firmware.

The RPi3 is working normally.

It just didn’t make sense, so Google was googled, again. That found a command to turn off the warning but with an interesting bit of further information.

https://www.raspberrypi.org/forums/viewtopic.php?t=82373

“avoid_warnings=2 additionally allows turbo when low-voltage is present.”

Tried it.

avoid_warnings=2
force_turbo=1
arm_freq=1200
core_freq=450
sdram_freq=450

And just watch the Pi3 go!!!

Chip’s running a bit hot though!

OTOH the chip is still running!

Chip’s running a bit hot though!

As I recall there was a bit of info from over on the Pi forums about turning off unused cores. Is this perhaps another instance of unused cores sucking power and generating heat?

Easy to over clock too,

1.5GHz and 2560×1440 @50Hz resolution.

RISCOSmark 2.01 (23-Sep-2015) by Richard Spencer 2003
Comparison with RiscPC SA 202MHz running RISC OS 4.02 800x600,256
(HD benchmarks are in kilobytes/sec)

MOS Utilities   5.23 (29 Feb 2016)
FileSwitch      2.83 (11 Nov 2014)
C Library       5.88 (29 Feb 2016)
USBDriver       0.80 (15 Nov 2015)
FileCore        3.68 (28 Oct 2015)
SCSIFS          1.28 (06 Oct 2013)
BCM2835 VDU device processor &4 type &FA000D68 revision &C tested at Sat,05 Mar 2016.13:45:35
Filing system: SDFS - CSD not set
Graphics Resoloution: 2560x1440, 16M colours

Test                                                   Benchmark
Processor - Looped instructions (cache)                  2974157    1672%
Memory - Multiple register transfer                         2008    1239%
Rectangle Copy - Graphics acceleration test                 1597     659%
Icon Plotting - 16 colour sprite with mask                 21773    1088%
Draw Path - Stroke narrow line                              5383     345%
Draw Fill - Plot filled shape                               1651     113%
HD Read - Block load 8MB file                              14894     499%
HD Write - Block save 8MB file                             18904     621%
FS Read - Byte stream file in                                699     337%
FS Write - Byte stream file out                              340     177%

The ‘Memory – Multiple register transfer’ speed looks unusually low (about 1/8 the speed of the Pi2 here: http://www.svrsig.org/HowFast.htm ). Otherwise, you’re basically getting ARMX6 performance for around 35 quid (sounds of cat getting well stuck in to pigeons)….

In some German online magazine they reported also to have problems with a too long USB cable which prevented them from overclocking.

I got the same success now, finally running at 1.2 GHz.

But when that “avoid_warnings=2” is set, it doesn’t recognize !Boot and I guess therefore also doesn’t want to change to the desired screen mode. I wonder how to fix that ? Anybody else seeing this ? …may be it’s all about getting the right power supply in the end !?

EDIT: I used now my main PC with an USB cable as a power source from a USB3.1 port…now it gets the !Boot but still needs the warnings disabled.

I checked my little benchmarks again, the 1.2 GHz now show clearly. NEON/VFP now in the level of an A9. The memory speed also doubled but is still way too slow…like George also wrote…is that an Risc OS issue ?

EDIT: Does somebody have a linux system running on Pi Mk 3 ? There seems to be an memory benchmarking app called “mwb 1.2.2-1”. May be we can see at the results from that if we have a Risc OS issue there…

Thanks Chris for running the memory test on unix. The result in the unix world seem to be okay =>

RPI2
AVG	Method: MEMCPY	Elapsed: 0.29763  MiB: 256.00000  Copy:  860.134 MiB/s
AVG	Method: DUMB	Elapsed: 2.45431  MiB: 256.00000  Copy:  104.306 MiB/s
AVG	Method: MCBLOCK	Elapsed: 0.30989  MiB: 256.00000  Copy:  826.090 MiB/s
RPI3
AVG	Method: MEMCPY	Elapsed: 0.24895  MiB: 256.00000  Copy: 1028.335 MiB/s
AVG	Method: DUMB	Elapsed: 1.37180  MiB: 256.00000  Copy:  186.615 MiB/s
AVG	Method: MCBLOCK	Elapsed: 0.24804  MiB: 256.00000  Copy: 1032.086 MiB/s

2560×1440 @ 50Hz

Chris, how did you achieve that? When I try is (using either ReadEDID or AnyMode) I get a one inch black band top and bottom. The mouse can be seen in it, but nothing else is there. And the mouse pointer seems to be offset from the actual position when clicking/dragging.

And the mouse pointer seems to be offset from the actual position when clicking/dragging.

A fix for something like that was checked in on 2nd March.

Chris, how did you achieve that? When I try is (using either ReadEDID or AnyMode) I get a one inch black band top and bottom. The mouse can be seen in it, but nothing else is there. And the mouse pointer seems to be offset from the actual position when clicking/dragging.

Put the following or similar in your config.txt file. If you end up with a blank screen you’ll need another machine to change the settings back.
If you have a suitable TV it will do 3840×2160 @24Hz.

hdmi_group=2
hdmi_mode=87
hdmi_cvt=2560 1440 50 3 0 0 1
#hdmi_cvt=1920 1080 50 3 0 0 1
max_framebuffer_width=2560
max_framebuffer_height=1440
hdmi_pixel_freq_limit=400000000

hdmi_cvt=<width> <height> <framerate> <aspect> <margins> <interlace> <rb>
Value                Default            Description
width                (required)         width in pixels
height               (required)         height in pixels
framerate            (required)         framerate in Hz
aspect               3                  aspect ratio 1=4:3, 2=14:9, 3=16:9, 4=5:4, 5=16:10, 6=15:9
margins              0                  0=margins disabled, 1=margins enabled
interlace            0                  0=progressive, 1=interlaced
rb                   0                  0=normal, 1=reduced blanking

I’ve come up with the following Basic ditty just to give a rough idea of clock speed. Not particularly scientific, but gives a ballpark figure and will show a change in speed. Using !Zap works for me, but there may be issues if I’ve tried running other things first. More investigation required on that front.

EDIT textile messing this bit up. Working on it! sorted! (Apologies to those who saw the first draft!)

10 : PRINT"Please wait"
20 : c%=0
30 : t%=TIME
40 : WHILEt%=TIME:ENDWHILE
50 : t%=TIME
60 : t%+=100
70 : WHILEt%>TIME
80 : c%+=1
90 : ENDWHILE
100 : c%=c%/1320
110 : PRINTc%

Then I added

temp_limit=50
avoid_warnings=2
arm_freq=1300

to CONFIG/SYS

The temp_limit is to try to protect my device and to try to speed up any reaction to the upper temp limit. (Although that may have been disabled by the warning thing.)
To start, with good power supply, when running the programme I was getting a figure higher than when I started with arm_freq=1200, but as it got warm this value fell. It continued to fall to about half.
I put an ice cube in a bag and applied to the CPU. (Don’t apply ice cube directly, it’s asking for trouble!) The figure went up again, but only to the value I got at arm_freq=1200. It would never return to the figure I got with arm_freq=1300.
It was flamin’ quick to boot though! :)

Tried 4K resolution.
hdmi_cvt=3840 2160 24 3 0 0 1
and pixel_freq 400000000
info button on remote from the TV show 2160P at 24Hz (after increasing the pixel_freq before it was 1080P at 60Hz) but i have the normal 1920×1080 on the desktop.
Do I need an updated MDF ? (I now have the standard built in for the PI-3)

Yes, you’ll need an updated MDF so that RISC OS knows that the screen mode is available.

There’s a good chance you can just use *ReadEDID (or *CreateModeFile) to get a list of modes straight from the TV.

Do I need an updated MDF ? (I now have the standard built in for the PI-3)

You could try anymode.

or

cvt.

or here’s the MDF entry generated with cvt,

# 3840 x 2160 (24.00Hz) RBlank 32bit (CVT)
startmode
mode_name: 3840 x 2160
x_res:3840
y_res:2160
pixel_rate:209750
h_timings:32,80,0,3840,0,48
v_timings:5,17,0,2160,0,3
sync_pol:3
endmode