nazouille wrote:Whre does the 333 frequency come from?
Why this number?
Is there any rules for this frequency?
I have it from the official raspbian rpi-config overclocking presets, look here:
arm_freq = core_freq * X = sdram_freq * Y
where X and Y are integer numbers, preferably X = Y.
note that significant difference please.
I played with many settings, I just picked out two configs I had in mind. As fas as I can see, corruption always kicks in with over_volt regardless of every other setting. (At least in my case)
stupid_boy wrote:you may need to play with avoid_pwm_pll too.
also different overvolts leads to slightly different behaviours, you are right, but not as above calculation.
in your examples there is no 'turbo mode'.
On http://elinux.org/RPi_config.txt#Overcl ... figuration
The GPU core, h264, v3d and isp share a PLL, therefore need to have related frequencies. ARM,
SDRAM and GPU each have their own PLLs and can have unrelated frequencies. The following is not necessary with "avoid_pwm_pll=1".
pll_freq = floor(2400 / (2 * core_freq)) * (2 * core_freq)
gpu_freq = pll_freq / [even number]
The effective gpu_freq is automatically rounded to nearest even integer, so asking for core_freq=500 and gpu_freq=300 will result in divisor of 2000/300 = 6.666 => 6 and so 333.33MHz.
therefore I don't think it matters here in which relation core, arm and sdram freqs are.