Selenium webdriver on IE9 is slower

We are working on dojotable using selenium webdriver 2.28(IE),WITH C#

the items in the dojotable will be filled on moving to last item in the table. my problem is that its very slow the same code works faster on other IE verision ,firefox etc.

Obsevered: on moving mouse manually it works faster, please help me to resolve the problem

i have tried using below but no luck

Actions builder = new Actions(objBrowser);
// Move cursor to the Main Menu Element
builder.MoveToElement(divSubSubelement).Click();
divSubSubelement.SendKeys(Keys.ArrowDown);