Each application running in Android is allowed a certain amount of memory. When it starts to fill up, the garbage collector (GC) will be called to free some of it so the application can carry on running (if it wasn’t called, the application would just close with an out of memory error). Every time the GC is called, it will take a few CPU cycles to carry out the task. By increasing the heap size, it is however possible to spare these cycles as it will take a longer time for the application to fill its memory space before GC needs to be called, resulting in the application running faster (at the cost of more memory). Some applications which may benefit from this are Gallery3D, image manipulation application, video players, and games in general. Most (if not all) applications are however written with low memory constrains in mind, so speed-ups may not be so visible.
So this little application just allows to change the size of the heap, as well as allowing to backup and restore the file where this setting is found. Root with system write and busybox are however required for this task. Good values are between 12 and 32, with 32 probably being the best value to settle on (your mileage may vary though). Incremental changes are always the best to see where you’re going if you try to go for the more extreme ranges.
It is available on the market (see QR code below) for free, and the AppBrain link is here.
P.S. Another nice thing is that if VM Heap Tool runs fine on your phone, so should Font Changer :)