//on $htttp success...
var dataRows = data; //data is your array with 2000 items
var delay = 0; //in milliseconds

//var to be used in ngRepeat
$scope.rows = [];

//each loop will extract the first objects from the array until the array is empty
while(dataRows.length) {
    delay += 20; //time span between every timeout call
    //using $timeout so it creates a new thread (don't lock UI)
    $timeout(function () {

        //take the first 50 items from the Array
        var thisChunk = dataRows.splice(0, 50);

        //append the 50 items to the $scope var
        $scope.rows.push.apply($scope.rows, thisChunk);

    }, delay);
}