1. Minimize iOS 11 Effects on Old iPhones

iOS 11 have lots of fancy animations and fluent motions to improve your visual experience. These stunning effects could be disasters to an old iPhone, as they used to take up resources and cause some overall lags. If you’re using an iPhone 5 or older (or even an iPad 4 or older), iOS 11 is likely run slightly slower on your device. You can easily turn off these gimmicks and see if your slow iPhone could run faster again.

How to Turn Off iOS 11 Effects:

1. Use the Reduce Motion feature: By disabling Reduce Motion in iOS 11, you can stop certain kinds of UI animations from eating unnecessary resources and causing your iPhone slow. To do so: Launch the Settings app > General > Choose Accessibility > Tap on Reduce Motion and turn the feature ON.
2. Turn Down The Graphics: The transparency and blur are used to convey visual depth in Apple mobile operating system, since iOS 7. On the other side, it consumes memories and slows down your iPhone too. To reduce the transparency in iOS 11: Tap on Settings > General > Accessibility > Increase Contrast and Turn on Reduce Transparency On.

2. Free Up Space on iPhone

To free up space on iPhone could have big improvements on a slow and old iPhone. One way to do that is to offload your photos and videos on your iPhone to your computer, to iCloud Photo Library, or to a backup service like Google Photos. Here are more tips on speeding up your slow iPhone by reclaiming more free storage.

How To Free Up Space on iPhone:

1. Try Storage Optimizing Recommendations
2. Enable 'Offload Unused Apps'.
3. Clear Messages, Voice Messages and Attachments
4. Delete Old iBooks and Podcasts.

3. Turn Off Background App Refresh.

Background App Refresh is one of new features in iOS 11 that allows app to refresh their content (download/upload/refresh) in certain network conditions. Turning off Background App Refresh may speed up your slow iPhone by stopping your apps from running automatically and without your awareness.

Turn Off Background App Refresh:

1. Launch the Settings app > tap on General > choose Background App Refresh > you can either turn the feature OFF altogether or individually. It’s recommended to keep certain apps refresh in background is you don’t want to do it manually.

4. Turn Off Automatic Downloads

As fast evolution of Apple mobile operating system, many labor-saving features in iOS 11 will save a lot of our time, meanwhile, it requires your iPhone to supply sufficient resources and keep robust. So getting rid of automated features, like Automatic Downloads in iTunes/App Store, will help keep your slow iPhone running faster, and help extend your battery life as well.

How to Turn Off Automatic Downloads:

1. Tap Settings > iTunes & App Store > and turn all the Automatic Downloads off. That may save your iPhone spare extra computing resources.

5. Clear Messages and Attachments

Message is an easily ignorable place that hold tons of junks slowing down your iPhone performance. If you rarely clean up your messages, then the accumulated attached images, videos, special effects in iOS 10 will probably be a storage and memory hog. Give a check on your Messages, especially these groups, and clean up useless ones. In iOS 11, you have more options to free up space and speed up your slow iPhone with recommended settings.

Enable Storage Recommendations for Message:

1. Open Settings > General > iPhone Storage > Scroll down to find Messages option > Enable these Recommendations.

Clear Outdated Documents and Data:

1. Continue to scroll down to find Documents and Data > Choose specific catagory > Click Edit > Select files > Click Trash can to lean up useless files.

6. Try Third Party iOS Monitor Apps

In the most cases, iOS regulates system memories contently and leaves us no choice to have a look at how it alloy the computing resources. However, if you’re curious about what on earth is slowing down your iPhone and want to put a hand on, then you can have a try with Traffic Monitor, an Activity Monitor app for iOS that allows you look at specific information for Data Usage, Device, Speed, Network, and Settings.

7. Close Tabs and Clear Caches in Safari

Back to age iPhone 4/iPhone 4s, Safari is definitely one of the most iOS resources swallower. Even after updating to iOS 11, quite a lot of users experienced Safari is slow, Safari stops responding, Safari quits unexpectedly, or has other issues. Follow steps below to fix Safari is slow on your iPhone problems.

How To Fix Slow Safari on iPhone:

1. Close Safari Tabs After Using: A tip to close out Safari tabs quickly is to do a long press on the double square icon, you'll then get the option to close all open tabs.
2. Regularly Clear Safari Caches: Tag Settings > Safari > Clear Historay and Website Data.
3. Optional Tips: More settings in iOS 11 will speed up Safari on your iPhone too, like Block All Cookies, Prevent Cross-Site Tracking, Stop Safari from Automaticall Saving Offline, etc.

8. Turn Off Location And Other iOS 11 Services

Location Services in iOS 11 uses GPS, Bluetooth, and crowd-sourced WLAN hotspot and cell tower locations to detect and fallback your location. It's popularly used in mainstream apps and greatly improved user experience for modern iPhones (iPhone 7, iPhone 8 and iPhone X). However, for the old iPhones like iPhone 5 or earlier models, Location Services will consume too many resources too. So turn off Location and services alike to speed up your slow iPhone.

How To Disable Location Services on iPhone:

1. Launch the Settings app and tap on Privacy > Choose Location Services >Now choose what apps can access your location and how.

9. Restart Your Old and Slow iPhone

Believe it or not, restarting an old iPhone (iPhone 5 or earlier) still is the most effective method to speed up a slow iPhone. Even though you shouldn't do it very often, but when necessary, restarting a slow iPhone will clear out the memory and can often fix unruly apps.