[pittendrigh]

Ok I'm revisiting my own thread a week later.
I have an old but capable quad core Linux box with a ton of memory.

Is my epub large? Not if it was a website. When it was text only I could manage the editor but as I began to add 2 to four 700 pixel wide images per page sigil became unusable.

Google shows me I am not alone. Many others have the same trouble. So I purchased Jutoh and that works just fine.

ls -l myhd.epub reveals:
-rw-rw-r-- 1 sandy sandy 1239863 Mar 26 19:42 myhd.epub

I have 22 chapters or epub *.xhtml sections averaging something like 4000 words each. On those 22 pages or sections I currently have a total 50 or so images. Boat building is complex and I need to add even more. All said images come from original jpegs almost 4000 pixels wide so I can knock them down to any size. I'm running with 700 pixels now because that's what I use on my boat building website.

I wish the sigil developers luck. But I do think they are going to have to fix the software. I am not the only one who has found it so slow it is not unusable. A keyword search on "sigil too slow" reveals many links, including other threads in this forum.

So. I conclude my trouble was NOT due to user error. That's my wrapup report. I am still a big fan of epub, especially epub3. But ........... I'm a bit sour on sigil right now, especially so because Jutoh works so well.