I was getting ready to downgrade my iPhone 3G from iOS4 back to 3, when I found out the simplest fix — do the FULL Reset. Hold the sleep/wake & home buttons until the Apple logo appears, ignore the Slide to Turn Off.
Cured the worst iOS 4 sluggishness! I'll let you know how often this is necessary, but so far… it makes a surprising improvement.
Failing that, report your 3G/3GS problems at http://www.apple.com/feedback/iphone.html, so Apple realises how much it's inconvenienced iOS 4 upgraders. There's enough whingers on the internet. Do something positive.
Cured the worst iOS 4 sluggishness! I'll let you know how often this is necessary, but so far… it makes a surprising improvement.
Failing that, report your 3G/3GS problems at http://www.apple.com/feedback/iphone.html, so Apple realises how much it's inconvenienced iOS 4 upgraders. There's enough whingers on the internet. Do something positive.