after page render event my asp.net page takes very long time to show up

I am new to stackoverflow forum and i need all ur help to solve my issue.

I have 3 list box controls inside a updatepanel with around 25000 records, i have a button which will show a popup(IFRAME) to filter those list box values.

initally i takes around 30 second to load the whole page(with 25000 records), but when i click filter button(to show the filter popup) it takes around 2 minutes to show the filter popup.

From page_load to Page_render it takes only 3 seconds, after page render it takes around 1.5 minutes to show the popup in the browser.

i checked using Ants profiler, after render event the CPU process is idle.

Please help me out to make that filter popup load faster.

Thanks 开发者_运维知识库in advance

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If showing the filter causes a postback, the issue with the amount of time it's taking is due to the amount of HTML being sent over the wire and rendering, especially if viewstate is enabled. Even an update panel posts the page with viewstate to the server.

So whatever you can load on the client-side - if you can load the filter popup via JavaScript, that would help.

HTH.