I was working on a rather large painting with a few layers. The size was 8000 pixels by approx 4600 pixels. When I tried to export the image it failed. So I thought I'd just merge all layers and try again. Clearly the memory was at it's limits.
Merging all layers resulted in half the image with the other half transparent. No good.
Next attempt was to merge layer by layer, this also failed with a memory error after a while.
So in the end I merged two, saved the file, closed artrage, opened the file, merged two layers etc. This worked.
Clearly the problem is the memory being taken by the undo's. Maybe an idea to add an option to say how many undos are being kept in memory OR to limit the memory the undos can take up. Also it would be great to get a "purge undo" button or something like it.
If you can get to the same result as merge all layers in the way I did then clearly the code can be optimised a bit better for these situations. Either way a 64 bit version would be great !