Crash/Freeze on Large Image File

[Ofnuts]

So, you have:

• 16GB RAM (according to Memory/Size)
  
• Probably 216GB of free disk space, at least on the drive where the Gimp swap file is (Swap/Limit)
  
• Gimp will use at most 8GB of the RAM, to keep image data (Cache/Limit)
  
• Since the RAM tile cache is nearly full, Gimp has started to swap over to disk (Swap/Occupied)
  
• You have 4.8GB of free RAM (Memory/Available)
  

Gimp splits image data (layer, masks, channels, and undo steps, that are for a good part plain copies of layers) in "tiles". When Gimp need memory for tiles, it picks it from the tile cache. If the tile cache is exhausted/full, it moves some of its contents to the swap file so that it can reallocate the cache to the new image data. However, since there is disk access, there is an I/O-induced slow down. How important is the slow down depends on several things (SD or HDD, file system, encryption...) but even in the good cases it is a nuisance and introduces long delays.

The tile cache size is defined in your preferences (System Resources/Resource consumption). The idea is to define a cache as large as possible, but not too large, because if the cache is too large, Gimp no longer benevolently swaps its data to disk in a way that is optimized for its own usage, but uses virtual memory like all other other apps, and this may lead to more memory used than you have RAM and your whole system starts swapping (and this impacts all other apps) and this is an even worse nuisance.

Since you have free RAM, you can definitely increase your tile cache to 12GB, and this will likely help somewhat. But you should keep on eye on the swap in the dashboard; when it starts to fill, things will be slow. don't abandon all hope on Gimp freezes, see if there is I/O activity or CPU activity on your system monitor (the Gimp dashboard is pretty much useless during these seizure episodes since it too is momentarily frozen).