Difference between Html.RenderAction and Html.Action

The difference between the two is that Html.RenderAction will render the result directly to the Response (which is more efficient if the action returns a large amount of HTML) whereas Html.Action returns a string with the result.

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Html.Action() – Outputs string

Html.RenderAction() – Renders directly to response stream

If the action returns a large amount of HTML, then rendering directly to the response stream provides better performance than outputting a string.