"After iOS 9 upgrade, many applications (safari, Facebook, etc.) load very, very slow, with a significant delay more than 10 seconds…who can solve this problem? any ideas to speed up iPhone after upgrading to iOS 9?"
Lots of iOS users hit this issue when they update their iPhone to latest iOS 9. The interface seems more sluggish, apps take longer to open or run, many applications hangs or even freezes and etc. even for those older iPhone models, such as iPhone 4s, 5. But there are some techniques we can use to fix iPhone slow issues and speed it up after upgrading to iOS 9.3/9.2/9.1/9 on OS X 10.11, 10.10 Yosemite, 10.9 Mavericks, 10.8 Mountain Lion etcc., whether you are using iPhone SE, 6, 6 Plus, 5S, 5C, 5, 4S or the new iPhone 6s, 6s Plus.
Hard Restart Your iPhone/iPad/iPod touch
Delete iPhone Unnecessary Files (Cache/Cookies/Temp Files/Apps)
Remove Any Unwanted Apps, Contacts, Photos, Notes, etc. from iPhone
Remove Motion and Animation Effects in iOS 9
The first and the simplest thing to fix lag and slowness in iOS 8 is hard restarting your iDevice. It's just a matter of pressing both the power button, and the home button at the same time for 10-15 seconds. Once iOS 8 restarts, it may be faster than before.
Going to Settings, General, Usage and then tapping manage storage to delete apps is OK, but to permanently delete them will need a professional tool. iPhone Care Pro for Mac is the one.
After the scan is finished, you can click on "Clean Now" to clear iPhone cache, cookies for safari, and more.
After you use iPhone Care Pro for Mac to completely delete cache, cookies etc., you can also use it to remove unwanted contacts, photos with the same program, to free up some memory.
Switch to "File Manager", and you'll find iPhone Care Pro for Mac can delete up to 8 types of iPhone files: Contact, Note, Calendar, App, Music, Video, Bookmark, and Photo. Select one to move on. Here we take Contact as an example. Click "Delete" on the menu to finish.
iOS 9 slow motion may also result from the animation effects. You need to disable motion and animation effects to improve the speed of iOS 9. Just go to Settings > General > Accessibility > Reduce Motion, and turn the switch on.
Hope these 4 tips can be helpful. If you have other tweaks, be sure to let us know, too.
If you accidently lost your previous files on your iPhone, you are free to use Tenorshare iPhone Data Recovery for Mac to restore your contacts, messages, pictures, notes, and more data.