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CBII Overclocking, How far does it go...

Started by PedroC1999, August 08, 2013, 08:29:53 am

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PedroC1999

Yes it ships at 960MHz, No it isnt at 1.5GHz, but how far can it actually go?


My friend pushed his RPi to 4Ghz under sub ambient situations, yes it is extreme, and unstable, but it booted and operated at said speed. I dont care about that, I want results of 24/7 overclocks that are stable etc, any info would be great

pcklee123

August 08, 2013, 06:53:59 pm #1 Last Edit: August 09, 2013, 01:39:37 am by pcklee123
My settins in script.bin for cubieboard 2. This lets me do cpufreq-set -g ondemand -u 1.4G  stable.
[dvfs_table]
max_freq = 140000000
min_freq = 720000000
LV_count = 11
LV1_freq = 1400000000
LV1_volt = 1800
LV2_freq = 1350000000
LV2_volt = 1720
LV3_freq = 1300000000
LV3_volt = 1650
LV4_freq = 1250000000
LV4_volt = 1600
LV5_freq = 1200000000
LV5_volt = 1525
LV6_freq = 1008000000
LV6_volt = 1475
LV7_freq = 912000000
LV7_volt = 1425
LV8_freq = 864000000
LV8_volt = 1300
LV9_freq = 720000000
LV9_volt = 1200
LV10_freq = 528000000
LV10_volt = 1100
LV11_freq = 312000000
LV11_volt = 1050

PedroC1999

So you got 1.4GHz stable, very interesting, have you got aftermarket cooling solutions??

pcklee123

No cooling, CPU is hot but not too hot to touch.

PedroC1999

What is the stock voltage, and what is it at now?

pcklee123

August 09, 2013, 11:16:23 pm #5 Last Edit: August 09, 2013, 11:27:20 pm by pcklee123
Stock voltage was probably 1.475V for anything above 1.08GHz.
Voltage now is probably 1.72V. Since cpufreq-info shows it at 1.39GHz instead 1.4GHz
Sorry after a bit more testing, I found it wasnt stable enough when certain programs run, CPU goes up to max and stays there eventhough usage is only 20-40%. I added an aluminium heatsink especially since room temperature here is about 32C. Seems better now.  cpufreq-set -g fantasys -u 1.4G. seems to work better at lowering the frequency at lower cpu usage.

PedroC1999

That is quite a voltage increase, bit high maybe.

How far can you go witha  max of 1.65v?

pcklee123

Probably1.3g max for me at 1.65v. But I think cooling should help. It is quite tedious to test it out.

PedroC1999

What you mean tedious? Could you explain the OC process on an ARM board?

pcklee123

Testing means
1)editing the script.fex file
2)doing fex2bin,
3) rebooting ,
4) set the cpu speed up bit by bit while running heavy loads. Some time it chrashes only after some minutes so need to wait


olouv

Any news on a stable overclocking config for CBII?

ratin

Quote from: pcklee123 on August 08, 2013, 06:53:59 pm
My settins in script.bin for cubieboard 2. This lets me do cpufreq-set -g ondemand -u 1.4G  stable.
[dvfs_table]
max_freq = 140000000
min_freq = 720000000
LV_count = 11
LV1_freq = 1400000000
LV1_volt = 1800
LV2_freq = 1350000000
LV2_volt = 1720
LV3_freq = 1300000000
LV3_volt = 1650
LV4_freq = 1250000000
LV4_volt = 1600
LV5_freq = 1200000000
LV5_volt = 1525
LV6_freq = 1008000000
LV6_volt = 1475
LV7_freq = 912000000
LV7_volt = 1425
LV8_freq = 864000000
LV8_volt = 1300
LV9_freq = 720000000
LV9_volt = 1200
LV10_freq = 528000000
LV10_volt = 1100
LV11_freq = 312000000
LV11_volt = 1050


Are you using the nand boot loader or micro SD? I am seeing that the script.bin entries are not read correctly by the nand bootloader.