[Warning] Never set VM Heap size too low on Galaxy Note

Although your thread title is right, your information can be a bit misleading.

The heap is a Java term that is used for storing application related resources into memory. For instance layouts, Java-code, strings or arrays with information. But in all versions below Android 4 (ICS), The default size an application needed was about 3MB for this. Bitmap's were placed outside the heap for some stupid reason. That's why one could get away with an heap size of 32MB or even lower. At the time this was probably a good idea because devices tended to have small internal memory (256MB or 512MB) and so Bitmap's could be swapped by the OS.

Anyway, with current devices and the current state of Android, the Bitmap's - which are a large portion of the allocated memory - are placed inside the heap. Also if you turn on to force GPU an app will use an extra of 8MB internal memory. So if you would add things up, you would at least need about 11MB for only starting the program. About 1MB for random values and quite a lot of memory for 'non-compressed' images. I guess about 16MB if your device would want to draw the entire screen without any compression with one 16-bit image! After which your app would use about 40MB of memory.

Now, take the Android launcher for example, that's an app with loads of images cached in memory. So my guess is that an app like that would use around 70 - 80MB of heap size just to run in GPU mode. This shouldn't be a problem with today's devices as we have more and more internal ram and processor speed available to use. So I think the ideal sweetspot for todays apps should be 128MB, as you could fit about ~6 apps running at once in the main memory. If you put the heap size at 256MB you could run about 3 apps at once. Including drawing.

I had been playing with the VM Heap size. My note was working fine with the value of 128m and 64m. However after tried changing down to 32m the Note's re-start stuck in glowing SAMSUNG logo with no choice but to re-flash ROM.

So guys be careful playing with this tweak. I won't touch it again and leave it at default setting.

Galaxy Note I : I did a big mistake... please help

Hi, guys.

It's a pity I didn't read your advice earlier, before I make my mistake.

I have the Galaxy Note I, rooted, and everything was working fine.

I had this evening the bad idea of trying to tweak VM Heap Size.

Previously set at 64m, and I tried to set it up at 36m. The application asked me confirmation for reboot, and from that moment, I cannot complete the boot anymore. I'm stuck at SAMSUNG logo, and that's all...

I didn't install CWM recovery or anything like that...

Do you have any idea of how I could get rid of that, please, without loosing all my data ?

(I'm posting from France, I'm sorry for my English, I hope you will understand my questions)

Constantin.