From version 2 onwards, PhotoRaw supports virtual memory. Here's what you need to know:

What is virtual memory?

Virtual memory means that if PhotoRaw runs out of physical memory (Ram), it will use parts of the iPhone or iPad's flash drive to store data. Previous version of PhotoRaw would have quit to the home screen if they ran out of memory. This means that very large images can easily be imported as well as converted to JPEG, even while multiple other apps are running in the background

The downside

There is however a downside to virtual memory. The flash drive is much slower than physical RAM. As a result, if PhotoRaw has to use virtual memory extensively, then operations that are memory intensive such as import operations and conversion to JPEG will slow down, under some circumstances by a factor of 2-4.

Controlling virtual memory usage

You can control PhotoRaw's use of virtual memory on the settings screen. By default, virtual memory is in auto mode. Three settings are available:

  1. Virtual memory off. This disables virtual memory. If you disable virtual memory, memory intensive operations will be faster, but if the device runs out of physical memory, PhotoRaw will quit, and the import operation or JPEG conversion will be abandoned.
  2. Auto. When set to auto, PhotoRaw will automatically detect the amount of memory available, and either use or not use virtual memory as required. This is the recommended setting - PhotoRaw will be as fast as possible within the limits of available memory. 
  3. Always On. Under rare circumstances, programs running the background can wake up and immediately require large amounts of memory while PhotoRaw is also using memory, leading to PhotoRaw quitting. In such situations, you can switch virtual memory to "Always On".