Rails - Mongoid : Slow problem between production and development

I have a problem on my Rails application.

I am in version 3.2.22 of rails and 2.2.5 of ruby connect to a mongodb 2.6.

The problem is that I have huge difference in performance on simple or even more complex queries.

For example :

I run rails c development and then I execute my function (quite complex) it responds after 30 seconds I run rails c production, I perform the same function as the previous one, it responds after 6 minutes 30 seconds, 7 times slower. So I try to copy pasted the configuration 'development' in 'production', but the result remains the same, same for the Gemfile.

I look in all the code of the project no difference between the environment production and development.

Do you know the differences in the heart of rails between these two environments? did anyone ever encounter the problem?

Importantly, I am of course connecting to the same database.

Thanks in advance.