I'm not aware of any new issues like this. Have you tried getting the latest service release?

How to get the latest service release - Infragistics Community

If that does not help, we will need you to provide more information or a sample so we can try to reproduce the issue and get it fixed.

Yes i use the latest Service Release (SR_2058).
You can see the difference beetween the v8.2 and v9.2 in this YouTube Video:
http://www.youtube.com/watch?v=t7S784gXj4M

OR

If you create a new project with the following code, you can see the difference better:
Please try to select all rows in v9.2 and then downgrade the project to 8.2 and try it again - now you will see UltraGrid with v8.2 works faster!

        private void Form1_Load(object sender, EventArgs e)
        {
            this.ultraGrid1.Dock = DockStyle.Fill;

            DataTable myTable = new DataTable();

            for (int iLoop = 0; iLoop < 20; iLoop++)
                myTable.Columns.Add("Column" + iLoop);

            for (int iLoop = 0; iLoop < 1000; iLoop++)
                myTable.Rows.Add(new string[] { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t" });

            this.ultraGrid1.DataSource = myTable;

            this.WindowState = FormWindowState.Maximized;
        }

Much thanks for answer + help!
myGil