Raspberry Pi 3 A+ over clocking

With the new Rpi 3 A+ it’s possible to over clock it slighty higher than other Pi models.

It seems to run stable with the following settings in config.txt.

arm_freq=1600
over_voltage=6
core_freq=600
sdram_freq=700
over_voltage_sdram=5
sdram_schmoo=0×02000020

Defaults on Rpi 3 B+ and A+

arm_freq=1400
core_freq=400
sdram_freq=500

Here’s the before and after results for RISCOSmark5,

RISCOSmark 2.04 (30-Dec-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             5.27 (14 Nov 2018)
FileSwitch                2.87 (08 Jun 2018)
C Library                 5.97 (11 Jun 2018)
USBDriver                 1.29 (19 May 2018)
FileCore                  3.75 (06 Jul 2017)
Shared Sound              1.20 (18 Jun 2016)
SCSIFS                    1.35 (20 Jul 2018)
LanManFS                  2.62 (04 Aug 2018)
ShareFS                   3.59 (11 Sep 2016) Access+
SharedUnixLibrary 1.14 (05 Sep 2015) (C) UnixLib Developers, 2001-2015
HAL-based system (BCM2835 VDU device) tested at Sat,17 Nov 2018.14:02:18
Filing system: SDFS:RISCOSpi.$.Bench
Graphics Resoloution: 1920x1080, 16M colours

Test                                                 Benchmark
Processor - Looped instructions (cache)                2832658  1592%
Memory - Multiple register transfer                      38033 23477%
Rectangle Copy - Graphics acceleration test               1378   569%
Icon Plotting - 16 colour sprite with mask               33888  1694%
Draw Path - Stroke narrow line                            9296   595%
Draw Fill - Plot filled shape                             2122   145%
Draw Render - Render draw file                            4174   460%
HD Read - Block load 8MB file                            23184   777%
HD Write - Block save 8MB file                           22755   748%
FS Read - Byte stream file in                             1184   571%
FS Write - Byte stream file out                            485   252%

Test                                                 Benchmark
Processor - Looped instructions (cache)                3272977  1840%
Memory - Multiple register transfer                      43960 27135%
Rectangle Copy - Graphics acceleration test               2034   840%
Icon Plotting - 16 colour sprite with mask               41340  2067%
Draw Path - Stroke narrow line                           11996   768%
Draw Fill - Plot filled shape                             2676   183%
Draw Render - Render draw file                            5194   573%
HD Read - Block load 8MB file                            23405   784%
HD Write - Block save 8MB file                           21005   690%
FS Read - Byte stream file in                             1344   649%
FS Write - Byte stream file out                            515   268%

1.6 GHz Sounds useful.

What temperature is that running at?

What method did you use to determine that it’s stable with the overclocked settings?

Have you fitted a cooler/heatsink/fan of some sort?

What temperature is that running at?

With a fan blowing air from underneath the board and no heat sink the temperature averages about 38C. At idle about 32C.
The ambient temperature is about 18C.

What method did you use to determine that it’s stable with the overclocked settings?

Normally there will be random lock ups and or aborts if the Pi boots sucessfully after a few minutes.
A good test is to leave mplayer playing a dvd res movie for half an hour.

Ah right.
When I was experimenting with overcocking my Pi 2, I tested stability with a script that repeatedly ran four instances of LAME encoding an mp3, then decoded it, then checked that the final .wav was the same every time with md5sum. (This was on linux)