Avoid page flickering - Publishing site having custom master page and page layouts

Hi,

I have a publishing site which contains a custom master page and custom page layouts.

When navigating between pages and subsites, the pages are getting flickered. I have used script manager in master page. I have few delegate controls as well.

when the pages are opened fo first time the page is having a flicker, and subsequent reopening of the page is not flickering it.

In the master page, I have the below:

<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager><SharePoint:AjaxDelta id="DeltaWebPartAdderUpdatePanelContainer" BlockElement="true" CssClass="ms-core-webpartadder" runat="server"><div id="WebPartAdderUpdatePanelContainer"><asp:UpdatePanel
		ID="WebPartAdderUpdatePanel"
		UpdateMode="Conditional"
		ChildrenAsTriggers="false"
		runat="server"><ContentTemplate><WebPartPages:WebPartAdder ID="WebPartAdder" runat="server" /></ContentTemplate><Triggers><asp:PostBackTrigger ControlID="WebPartAdder" /></Triggers></asp:UpdatePanel>

I do not have any update panels in my custom page layouts. What should be done to avoid page flickering when loading?

The overall width of the page increases from that of master page and then adjusts to the master page width. 

How to fix this?

Thanks