I mainly used Photoshop as a subscription until now as it was the best tool that had both image editing and painting on Windows. GIMP was fine for image manipulation, but for painting both GIMP and MyPaint had a strange issue because of GTK, and cursor would just skip or draw in random places on the screen.

Now I'm planning to drop PS subscription and go on with GIMP as my image editing program, and I wish to use Krita as a painting software (buying Paint Tool SAI is the other option), now that it has a Windows version.

I tried it a bit last night, but I noticed some slow downs with certain brushes (Chalk with mirror mode on, near the edges of the image) and also some crash while trying some vector based tool (don't remember which).

My questions are:
1. Will it perform OK for large images?
2. Should I expect slowdowns and/or crashes often?
3. How fast are saving times for huge files (7k wide images)?
4. I've enabled GPU support and texture buffers in Settings, is that OK? Do I need certain hardware specs to enable that?

My desktop is an i7 920 processor, 18 GB of memory, 2GB 760 GTX Video card, normal (non-SSD) hard disk.

Thanks!

1. Can't answer that as ok performance may be perceived differently. I suggest you simply test it.
2. The desktop version is currently build from the development branch, so there can be crashes. It's updated regularly and becoming more and more stable these days. Feel free to report anything that happens.
3. Depends on the number of layers and their content and the colorspace. You probably have to test that for your images.
4. If you have enabled it and didn't encounter problems so far it most likely ok. GTX 760 should be more than enough.

Thanks for the quick answer. I'll do some tests for point 1 and 3 that match my usual workflow and I'll post here the results.