AJAX中Timer控件

<%@ Register Assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" Namespace="System.Web.UI" TagPrefix="asp" %>
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:Timer ID="Timer1" OnTick="Timer1_Tick" runat="server" Interval="10000"/>
<asp:UpdateProgress ID="UpdateProgress1" runat="server"><ProgressTemplate><div class="loadcs"><img alt="loading" src="Images/indicator.gif"/>&nbsp;数据加载中,请稍候</div></ProgressTemplate></asp:UpdateProgress>
<div id="firstrow">
    <div id="hdleft"><img alt="taisol" src="Images/taisol_logo.jpg" width="149" height="34" border="0" /></div>
    <div id="hdright"><span class="m"><img alt="log" src="Images/ecrimg.jpg" width="122" height="24" /></span></div>
</div>

        protected void Timer1_Tick(object sender, EventArgs e)
        {
                this.liEcr.Text = "<img src='images/newse.gif' align='absbottom' />&nbsp;申请单&nbsp;<font color='gray'>|</font>";
        }

感觉很影响系统性能。