This macro builds my navigation.  It takes 2-3 seconds to run.  I have it cached, but I'd like it to go faster on first run.

var ulClass = String.IsNullOrEmpty(Parameter.UlClass) ? "" : String.Format(" class=\"{0}\"", Parameter.UlClass); 
    var ulID = String.IsNullOrEmpty(Parameter.UlID) ? "" : String.Format(" id=\"{0}\"", Parameter.UlID); 
    var selectionCriteria = String.IsNullOrEmpty(Parameter.Selection) ? "" : Parameter.Selection;
    
    <ul@Html.Raw(ulClass)@Html.Raw(ulID)>

            @foreach (var item in Model.AncestorOrSelf().Descendants().Where("Level <= 3 && " + @Html.Raw(selectionCriteria) + " == true").OrderBy("level, sortOrder"))
            {
                var selected = Array.IndexOf(Model.Path.Split(','), item.Id.ToString()) >= 0 ? " class=\"selected\"" : "";
                <li>
                    <a@Html.Raw(selected) href="@item.Url">@item.Name.ToUpper()</a>
                </li>
            }

    </ul>

Here's the offending line:

Model.AncestorOrSelf().Descendants().Where("Level <= 3 && " + @Html.Raw(selectionCriteria) + " == true").OrderBy("level, sortOrder"))

I have navigation elements that are 2 levels down from my root.  I have around 650 nodes total.  I think this query is looking through all the elements and not just looking through the first few levels.

I'd like to restrict the query to only look for the first <= 3 levels, then apply the where clause.  I've tried Decendants(3) but that didn't work.

Any ideas how I speed this up?