Answers.Body: <p>As <a href="https://ebooks.stackexchange.com/users/107/mmmmmm">@mmmmmm</a> suggested, breaking up the file into chapters ended up working and made loading the file much faster. I ended up making 256kb the largest single file and that worked well.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-08-03T17:45:15.290Z
Answers.LastActivityDate: 2021-08-03T17:45:15.290Z
Answers.UserDisplayName: gfaster
Body: <p>I am generating very large epub3 books (almost all text) and I have noticed severe performance issues when trying to read them. Is there any format changes I can make to make reading performance better?</p>
  <p>the files in my epub are as follows:</p>
  <pre><code>│   mimetype (1KB)
  │
  ├───EPUB
  │   │   cover.xhtml (1KB)
  │   │   nav.xhtml (36KB)
  │   │   package.opf (2KB)
  │   │   s04.xhtml (5.3MB)
  │   │
  │   ├───css
  │   │       epub.css (1KB)
  │   │       nav.css (1KB)
  │   │
  │   └───images
  │           cover.png (21KB)
  │
  └───META-INF
          container.xml (1KB)
  </code></pre>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-06-12T13:54:32.800Z
Comments.Text: Break the html up into chapters
Comments.UserDisplayName: mmmmmm
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-07-30T02:00:24.383Z
Comments.Text: Do you actually have ~5 MB of text in the so4.xhtml file? How much is actual text that you've input, and how much is XML? Is all that needed?
Comments.UserDisplayName: DrMoishe Pippik
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-08-01T07:33:23.577Z
Comments.Text: This EPUB was the result of scraping hundreds of pages, and was pretty well reduced to just <p> and a a few <div> tags. Breaking it up was the only real solution in this case.
Comments.UserDisplayName: gfaster
Tags: <epub>
Title: EPUB 3 large file leading to poor performance
UserDisplayName: gfaster
ThreadText: # EPUB 3 large file leading to poor performance
  
  (Asked by: username_0 on 2021-06-12)
  
  I am generating very large epub3 books (almost all text) and I have noticed severe performance issues when trying to read them. Is there any format changes I can make to make reading performance better?
  
  the files in my epub are as follows:
  
  ```
  │   mimetype (1KB)
  │
  ├───EPUB
  │   │   cover.xhtml (1KB)
  │   │   nav.xhtml (36KB)
  │   │   package.opf (2KB)
  │   │   s04.xhtml (5.3MB)
  │   │
  │   ├───css
  │   │       epub.css (1KB)
  │   │       nav.css (1KB)
  │   │
  │   └───images
  │           cover.png (21KB)
  │
  └───META-INF
          container.xml (1KB)
  
  ```
  
  **Tags:** epub
  
  > **Comments:**
  > **username_1**: Break the html up into chapters  
  > **username_2**: Do you actually have ~5 MB of text in the so4.xhtml file? How much is actual text that you've input, and how much is XML? Is all that needed?  
  > **username_0**: This EPUB was the result of scraping hundreds of pages, and was pretty well reduced to just <p> and a a few <div> tags. Breaking it up was the only real solution in this case.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2021-08-03. Score: 1 | Accepted answer
  
  As [@username_1](https://ebooks.stackexchange.com/users/107/username_1) suggested, breaking up the file into chapters ended up working and made loading the file much faster. I ended up making 256kb the largest single file and that worked well.
  
  
  ---
  
  