Are jQuery's :first and :eq(0) selectors functionally equivalent?

I'm not sure whether to use :first or :eq(0) in a selector. I'm pretty sure that they'll always return the same object, but is one speedier than the other?

I'm sure someone here must have benchmarked these selectors before and I'm not really sure the best way to test if one is faster.

Update: here's the bench I ran:

/* start bench */
for (var count = 0; count < 5; count++) {
    var i = 0, limit = 10000;
    var start, end;
    start = new Date();
    for (i = 0; i < limit; i++) {
        var $radeditor = $thisFrame.parents("div.RadEditor.Telerik:eq(0)");
    }
    end = new Date();
    alert("div.RadEditor.Telerik:eq(0) : " + (end-start));
    var start = new Date();
    for (i = 0; i < limit; i++) {
        var $radeditor = $thisFrame.parents("div.RadEditor.Telerik:first");
    }
    end = new Date();
    alert("div.RadEditor.Telerik:first : " + (end-start));
    start = new Date();
    for (i = 0; i < limit; i++) {
        var radeditor = $thisFrame.parents("div.RadEditor.Telerik")[0];
    }
    end = new Date();
    alert("(div.RadEditor.Telerik)[0] : " + (end-start));
    start = new Date();
    for (i = 0; i < limit; i++) {
        var $radeditor = $($thisFrame.parents("div.RadEditor.Telerik")[0]);
    }
    end = new Date();
    alert("$((div.RadEditor.Telerik)[0]) : " + (end-start));
}
/* end bench */

I assumed that the 3rd would be the fastest and the 4th would be the slowest, but here's the results that I came up with:

FF3:    :eq(0)  :first  [0] $([0])
trial1  5275    4360    4107    3910
trial2  5175    5231    3916    4134
trial3  5317    5589    4670    4350
trial4  5754    4829    3988    4610
trial5  4771    6019    4669    4803
Average 5258.4  5205.6  4270    4361.4

IE6:    :eq(0)  :first  [0] $([0]