I am using MVC 4 on Azure and it loads very slowly (minute). Here is the loading time of several pages: 
(6.9 minutes was when I tried to load 7 tabs with different pages)
This problem does not occur when I use the Azure emulator locally.
I tried using an extra instance and using Remote Desktop to run the site locally, and it was just as slow. I also tried using IIS Express and regular IIS, and there was nothing there.
I created a completely new MVC project using the "Internet Application" template, which includes security, and it is very slow, so I am sure that the other things that I use in my project do not cause problems. Here is the load times only with the default MVC project: 
I initially used separate affinity areas for my membership database and my website, but I tried to use the corresponding affinity groups both on the empty form-validated MVC template and with my project.
Repeated page does not significantly improve their speed.
I also tried to create only an MVC site without authentication, with a 10x5000 table created:
<html> <body> <table> <thead> <tr> @for (int i = 0; i < 10; i++) { <th>@i </th> } </tr> </thead> <tbody> @for(int i = 0; i < 5000; i++) { <tr> @for(int j = 0; j < 10; j++) { <td>Row @i , column @j</td> } </tr> } </tbody> </table> </body> </html>
This loads normally, both locally and in the cloud. Even with a cold start, it is only ~ 10-15 seconds.
So, I'm sure the problem is with the ASP.NET profile / membership / authentication, but only when deploying it to Azure (since I use the same Azure SQL database with Universal Providers when running locally, and there is no such slowdown).
I expected this problem to become more common, but the only thing that really seemed appropriate was the following: social.msdn.microsoft.com/Forums/en-US/windowsazuremanagement/thread/7d3323d8-571b-4b8f-9fdb-bd5ccc6c39b7 ( maybe this is: https://stackoverflow.com/a/4646263
I am working to try, as suggested in this thread, at windowsazure.com/en-us/manage/windows/best-practices/