Many have been plagued by the slowdown that is iOS4 on iPhone 3G. So much so that many have been tempted to go through a somewhat painstaking process to downgrade their iPhones. Apple Genius Bar gurus closely involved with the customer issues also confirm having to assist customers downgrade due to performance issues.
But this evening, renowned 17 year old iPhone hacker @comex points to what seems to be a helpful post on the ModMyi.com forums. Apparently the performance issue may have something to do with spotlight, and by disabling this feature (Settings/General/Spotlight) (Settings-General-Home Button-Spotlight-thanks for the correction in the comments!) many have seen large performance gains. Let us know in the comments how this tip works for you if you’re currently using a 3G and iOS4.