The findAll method in UIAutomation is very slow

This is my code: 

window.FindAll(TreeScope.Children, new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.Edit));

It took three minutes to execute the command......

I want to get the arrays that findAll() method returns, But this method very slow, It is have update?

If you can, I'd like to hear your suggestion, Thanks.

The platform I used is .Net framework 4.0