vBulletin 3.8.7 login consistently slow on Internet Explorer 9

[trankin]

Hi there,
We're having a slow login issue with IE9. We tested with many other browsers, and could not replicate the issue. This issue only occurs in IE9 on MS Windows 7.

Here is my observation:

• When we're sending IE7 Compatibility Header(Internet Explorer 7 Compatibility Header: Yes), IE9 browser is forced to render the content in IE7 mode and it does not display/allow IE9 Compatibility button. In this case login is slow.
  

• When we disabled the IE7 Compatibility Header(Internet Explorer 7 Compatibility Header: No), IE9 offers the Compatibility button to the user. If users want to render the content in Compatibility Mode, they can click on it, and page will reload in IE9 Compatibility Mode. If you try logging in at this point, you will be logged in instantly. But if you didn't click on the button, and tried logging in, it will still be slow-login.
  

Any thoughts! Any help would be much appreciated.

[Wayne Luke]

The IE7 rendering engine is slow. It always has been slow. When you send the compatibility header, IE uses the IE7 engine, not the IE9 engine. Therefore it is going to be slow.

If you site appears correctly without the header being sent, then turn off the option. If not, then either fix the layout or turn on the option. We really can't fix how Microsoft designs IE though.

[trankin]

Thanks for your input, Wayne.

I do not see any issue with turning that option (IE7 compat. header) off on my board. But in my test case, although I have disabled that option, logging into the site on IE9 without clicking on compatibility button, is still abnormally slow. Many of our users are not techies and they wouldn't know they have to click on the compatibility button on IE9 in order to gain faster login.

Are you saying that it could be a template issue on my site that slowing down the logins on IE9? Or is there a specific header that we need to send for IE9 browsers?

Thanks for your time.

[Wayne Luke]

What is the site URL?

[trankin]

Can I PM you the URL?

[Wayne Luke]

That would be fine.

[trankin]

Just PM'd you the site URL.

[trankin]

Find anything?

[Wayne Luke]

From my test the delay is the response from the server when requesting login.php the first time I tried to login. Subsequent logins went quickly. Have to remove my internet cache to recreate the slow login after the first time. Make sure login.php isn't caching results which can probably slow down individual logins. I don't know why it is limited to IE9 though. After login.php is loaded, the redirect is very quick.

You can view this with a clean cache and using the Developer tools in IE9 (F12).

[trankin]

Thanks for the information, Wayne. I will take a look on the login.php issue, and let you know on that.