simple_form: What is the expected slowdown of using SimpleForm?

I was investigating some slow view rendering in our application.

We had a partial that was rendered many times, which looked like this. I had perhaps stupidly opted out of most Simple Form goodness, but I guess for consistency’s sake, thought this would be ok.

<div class='sortableItem variant' data-item-id='<%= f.object.id %>'>
  <div class="variant-creator-row">
    <div class="variant-details">
      <%= f.input :text, label: false, wrapper: false, as: :string %>
    </div>
    <div class="variant-option-value">
      <%= f.input :option_1_value, label: false, wrapper: false %>
    </div>
    <div class="variant-option-value">
      <%= f.input :option_2_value, label: false, wrapper: false %>
    </div>
    <div class="variant-option-value">
      <%= f.input :option_3_value, label: false, wrapper: false %>
    </div>

    <div class="variant-hidden">
      <%= f.input :hidden, label: false,  wrapper: false %>
    </div>

    <div class="variant-delete survey-answer-delete">
      <a href="#" class="text text-danger">delete</a>
      <div class="hidden">
        <%= f.input_field :_destroy, as: :boolean, label: false, wrapper: false %>
      </div>
    </div>
  </div>
</div>

<%= f.hidden_field :field_kind, value: 'multiple_choice' %>

Worth noting, this f value is coming from a “simple_fields_for” call.

This partial was getting rendered many times, and looking at my logs, each one was taking > 200 milliseconds! eek! https://gist.github.com/maxwell/12cd7e949cae4ea60766

Changing this to just be normal Rails helpers radically reduced render time, to about 5 milliseconds per partial, 40x faster!

https://gist.github.com/maxwell/f7b6c1bc6625f6b5c3e7

I realize that it is reasonable to know that there would be some overhead, and perhaps one should not use SimpleForms for simple forms which are rendered many times, but is this the kind of overhead we should expect? Am I doing something incredibly stupid to cause this behavior?

I am currently using simple_form (3.1.0.rc1), and Rails 4.1.10

I love using SimpleForm, thanks so much for all the hard work you guys put into it!