Thank you for contacting us.
Since Q2 2009, our RadForm has been completely re-written from scratch to eliminate most of the performance and redrawing issues you describe. I would recommend that you download the latest version Q2 2009 SP1 which contains many new features and a lot of bugs are fixed.
Otherwise it is normal for our framework to add some additional overhead upon loading. We have theming, styling, animations and all this new functionality is the reason for some performance costs. This performance hit however is minimal and compared to the level of flexibility our components add, it may be completely discarded.
the Telerik team