I am using RPi4 for a while and I found some problem playing videos on VLC and you-tube. After searching a long time I found that these problems can be solved by increasing GPU Memory. I found that option in raspberry pi configuration. I need to know , 1. What is the maximum and minimum memory value for GPU? 2. What is the optimum value of GPU memory? 3. Will I face any problems if I set the value very high or very low?
Here's the relevant part of the official docs.
Min and max:
GPU memory in megabytes, sets the memory split between the CPU and GPU; the CPU gets the remaining memory. The minimum value is 16; the technical maximum value 944 [for the RPi 4]. The default value is 64, values above 512 will not provide increased performance and should not be used.
The Raspberry Pi 4 3D system has it's own Memory Mangement Unit (MMU) so textures and other GL resources are not allocated from the gpu_mem but Linux system memory instead. This means that gpu_mem can be set to a lower value, so even if you are using the H264 and camera then 128MB will probably be enough.
You shouldn't need to set it beyond the default value in the plain Raspbian /boot/config.txt. Max value is 128M.
Setting it beyond 128M can leave your Raspberry Pi 4B unbootable.
GPU memory on a RPi4B isn't used in the same way as on earlier Raspberries.