Just found this little trick online! If you find your iPhone is crazy slow at loading Safari, or apps keep crashing then it's worth a try.
Marc Forrest discovered this hack get your iPhone running more efficiently.
• Go to your homepage. Press and hold the power button until you see the ‘Slide To Power Off’ message.
• Take your finger off and hold down the home button for 5 seconds
This should clear your RAM memory which means your phone should run a lot faster
Let us know how you get on!