Alternative to FieldCollection and FieldCollection Table i have a fieldcollection field in a entity form type with FieldCollection Table display, and its set to unlimited value. In this field collection there are 5 fields.
After some research I found that after insert 20/30 items, field collection slows down considerably. Infact, in my entityform, after 40 items of fieldcollection, increases the data loading time.

I'm looking for an alternative to fieldcollection with the ability to display the field in table such as field collection table.

can you help me?

Thanks
Oh, good question. 

combined with some fancy view work, you could use pretty much any fieldable entity in Drupal to do this. 

You could use another content type with entity relationships to link the two. You can render it with an Entity Reference Views Widget and use a views table to format that output. 

If you don't want to use a content type, you can also explore custom entities. 

Reading: 


https://www.sitepoint.com/build-custom-drupal-entities/
https://www.phase2technology.com/blog/developing-a-custom-drupal-entity/
http://www.trellon.com/content/blog/creating-own-entities-entity-api


Now, if you don't want to have to try and do this in code, there is also a great module called ECK (Entity Construction Kit) which allows you to build fieldable entities and use them just like any other all from within the Drupal admin UI.

Hope this helps.