We are having a problem with this setup when we have more than 500 rows in the gridview.
The business requirement does not allow us to do paging as we are replacing a classic ASP app and have to match it.
We have discovered that the problem occurs when rendering the page, as the server-side code has completed.
If we run this in Chrome, the page renders in a few seconds, but in IE9 the same data can take over a minute.
I've seen articles like this:
http://blogs.msdn.com/b/tom/archive/2008/09/15/slow-performance-of-a-gridview-inside-an-updatepanel.aspx but it didn't work for us.
I'm considering changing from a gridview to a listview but I'm not sure if that will have everything I need.
Any ideas?