CMS Orchard's action low performance

Question

I am trying to understand why our CMS Orchard is performing very low with our Web application. I took an example of the Edit action... Here is the code and the profiler

namespace Orchard.Core.Contents.Controllers {
    [ValidateInput(false)]
    public class AdminController : Controller, IUpdateModel {

        //...

        public ActionResult Edit(int id) {
            var contentItem = _contentManager.Get(id, VersionOptions.Latest);

            if (contentItem == null)
                return HttpNotFound();

            if (!Services.Authorizer.Authorize(Permissions.EditContent, contentItem, T("Cannot edit content")))
                return new HttpUnauthorizedResult();

            var model = _contentManager.BuildEditor(contentItem);
            return View(model);
        }

        //...
}

We have some Web API, named FrontServices, Orchard uses to update data in the Oracle DB, but these actions does not seem to take much time...

The AdminControler.Edit is taking a lot of time, that maybe because of the threads or other things... maybe because of Authentication... I don't know exactly what code from the controller takes so much time, did someone experienced such kind of problems with this CMS?