For those of us who need more room...
XMEM2 @ https://github.com/xxxajk/xmem2
xmem2 is an xmem compatible library with autosize features.
Supports both RuggedCircuits RAM expansions automatically. Supports Andy Brown's RAM expansion too.
Can support up to 255 banks of external memory, with minor sketch changes.
NEW: Supports moving the stack to external memory. You can even specify how much.
NEW: XMEM2 now supports real preemptive multitasking!
On the QuadRam, 16 tasks are possible.
Each task has it's own stack, and malloc arena.
Tasks are switched in round-robin order.
The shared stack/malloc arena area is 32KB and you can split it how ever you wish.
Best of all *NO RTOS OVERHEAD*
Multitasking Demo @ https://github.com/xxxajk/testMultitask
NEW: CPU cycle friendly Sleep()
Lock_Acquire(), Lock_Release(), Yield()
Ability to determine parent task.
Ability to detect when a task is running or done.
Ability to determine if parent task owns child task.
More features coming as needed.