This concerns WPtouch Mobile Plugin 3.3.4 going back to 3.3.
I'm running WPtouch Mobile Plugin on one server/hosting where it doesn't cause admin to time out. However, on another host, it does often (95%+) time out even with the time-out set to really long (+5 minutes). To get anything done in admin, I'm having to use FTP to change the subdirectory name. When I'm done with the admin work, I change the name back and reactivate the plugin.
When I reactivate, I can get around in admin easily during that same login session. Therefore, the problem accumulates somehow over time. If I log out and log back in quickly, it doesn't time out or seem to take more than the normal time. Therefore, I don't think there's another plugin conflicting right away, but it is hard to check for obvious reasons.
I tried copying the WPtouch plugin to another subdirectory (pluginsX) and renamed the original plugin subdirectory pluginsY while then renaming pluginsX to plugins. Then I tried accessing admin, which had timed out when I logged in for the first time today. After WordPress finished deactivating all the other active plugins, it loaded quickly. Refreshes loaded quickly.
I reversed the subdirectory names and one-by-one, reactivated the plugins. The admin loaded very quickly after each reactivation.
I'm suspecting W3 Total Cache. I reloaded admin a few minutes later, and it loaded in about 11 seconds when it had been loading in about 1 second. I purged all the caches, and it loaded in about a second again. I re-purged the caches and immediately deactivated just W3 Total Cache. I decided to leave it that way for several hours, which ordinarily would be plenty of time for the slow-loading admin issue to show up.
It continued to load normally. Therefore, I'm reasonably sure that the problem is between WPtouch and W3 Total Cache and that the problem builds up the more W3 builds the caches.
Mind you, this is only with one host and not the other.