I have an iPad app that's crashing due to low memory. However, Instruments doesn't show any significant amount of memory allocated using ObjectAlloc - it stays under 1MB for the lifetime of the application. Leaks shows less than 1kB leaked over the course of the run. Memory monitor shows the free memory on the devices drop significantly with use, eventually dropping to the point that it's out of memory. Here's a screenshot from Instruments:

I'm totally stumped. As far as I can tell, this basically says that as far as my app is concerned, I'm never using more than about 750kB, but that the device is still running out of physical memory, which is causing my app to crash/force exit.

I'm new to debugging memory issues with XCode. Am I measuring this wrong? Is there another way to see where this memory is going?