Misconfigured Max clock speed affects all Allwinner F1C100S devices

[MrRocketFX]

The default max clock speed is set to 900mhz which will lock up the device if set to or above 798mhz. The proposal is to set the "cpuMax" value to 798mhz to prevent lockups.

[Rezzy-dev]

Here are the technical specs for the CPU:

https://linux-sunxi.org/F1C100s

Normal operating frequency is at 533 MHz, actually.

The maximum operating frequency it is able to perform at actually seems to vary from device to device:

https://www.rghandhelds.com/handheld-specs

(Some are marked at max 798 MHz, and others at max 702 MHz here.)

According to the original marketing/documentation, this processor supports a speed of up to 900 MHz, but in working implementation/practice the maximum speed tends to vary from device to device, and to be lower, somewhere around 700 MHz.

I'm not sure if the maximum setting should be changed, as overclocking is always known to cause problems. You're taking a risk trying to overclock your processor in the first place. I think it may be better to allow for the full range rather than limit the user in the UI. We don't know if a particular (or future) device may actually support up to 900 MHz (which is the upper technical, physical performance limit of this CPU).

But if you wish to change it on your system, simply edit "gmenu2x/gmenu2x.conf" on your SD card and set the "cpuMax" setting in it to your desired value (as you have already done).

[Apaczer]

https://github.com/gameblabla/bittboy_oc

You can check from above OC table, that anything beyond 798MHz have no practical usage. However users from first PocketGO line claims that overclocking above 732MHz may cause any running program to close on itself. Moreover one person from support stuff with Powkiddy V90, have stated that 828MHz should give best performance results (see PCSX-Rearmed Config Library). Can't say from where these mismatches come from for one CPU, but personally I've found 798MHz to be stable and effective OC value (on V90).

[Rezzy-dev]

The mismatch comes from the fact that the hardware used in these devices, even along the same model/line in individual devices, varies. So the components that make up the motherboard, the memory, etc., and the work that was done to fit them together, may actually differ between two PocketGos or between two PowKiddy V90s.

In other words, no two devices are exactly the same, even if they carry the same processor. The maximum working speed of the processor is impacted by a lot of other factors. And just because the processor can run at 900 MHz tops does not mean that the whole system can. Maximum performance varies with each device (the components used to make them) and their age.

[Rezzy-dev]

These units are assembled in various factories in China, and multiple factories often work to produce the same model/product/brand while each doing their own thing. While basic quality assurance exists, there's no specification that states exactly what needs to go into each device (only rough specs) -- so if there is other stock/materials that can be used, and that serves to save on manufacturing costs, you can sometimes end up with very different hardware in the same device, produced in two different factories.

Both devices will work well and will do what they're supposed to do, but when it comes to things like top performance, their behaviour may differ quite a bit due to the different internal components used in their manufacture -- despite the fact that they are both a PowKiddy V90, for instance.

Hope this helps to better understand it.