How to improve iOS 4 performance on iPhone 3G

If you update to iOS 4 on an iPhone 3G the performance, to but it mildly, will be poor to the point of frustration. When I first updated mine it was so bad I didn't want to use it -- though admittedly I'd gotten used to an iPhone 3GS, then iPhone 4, and it's never easy to go back.

iPhone Forums and stoovie to the rescue. Turns out there are a few things you can do to make it faster to the point of livable:

  • Turn off Spotlight. Go to Settings, General, Home Button, Spotlight Search and just turn it all off. iPhone 3G is so resource constrained Apple wouldn't even enable wallpaper. Indexing Spotlight in the background seems to be the straw that breaks the performance's back. With Spotlight off, it's a usable device again.

If you're still having trouble there's always the nuclear option:

  • Restore as a new iPhone. Do a clean wipe and re-install without copying back your data. It's a royal pain in the apps but there seems to be something borked about including old data that just slows stuff down. I got an immediate speed boost with a clean install as well.

Unfortunately, it's Jailbreak territory if you want to downgrade from iOS 4 to iOS 3.1.1 again, and many users seem to have problems even with that method. So try the above methods first and let us know how they work for you.

[Yeah, my iPhone 3G has a cracked screen but that's totally unrelated to the performance issue, poetry aside]

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Rene Ritchie

EiC of iMore, EP of Mobile Nations, Apple analyst, co-host of Debug, Iterate, Vector, Review, and MacBreak Weekly podcasts. Cook, grappler, photon wrangler. Follow him on Twitter and Google+.

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Reader comments

How to improve iOS 4 performance on iPhone 3G


Unchecking the spotlight search options maybe helps a little, but the phone is still crazy slow. Probably at least 50% slower. Thanks, Apple.

I have a 3GS and after the iOS4 install my email doesn't automatically check evey 15 minutes like it did before.

Something that did help for me is making sure Safari does not have a web page loaded. When it does Safari apparently clogs op the RAM making the iPhone 3G almost too slow to use. Just make sure Safari only has a blank page visible when you exit the browser. The rest of the Phone will work remarkable faster!

It's sucks apple come with such stupid ios4. My iPhone seems to be so stupid as Steve jobs! Well,I thinks this is the end of life for the iPhone 3G.

I have a Jailbroken iPhone 3G upgraded to iOS 4.2.1 while preserving iOS 3.1.3/5.12.01 Baseband for my unlock. I tried to disable Spotlight Search for all the listed items and did a couple of Hard Cold Resets (Power + Home) and could hardly notice any significant performance. I had better performance with iOS 3.1.x, however iPhone 3G performance is far beyond that of the iPhone 3Gs and 4 either on iOS 3.x or 4.x.
I think this because mainly of the low memory amount of 128MB compared to double and quadruple amounts in the other 2 models 3Gs & 4G (256MB & 512MB). Also the slower processor has an impact, but the major performance bottle neck is the amount of available RAM which is usually in the range of 10-15 MB free.
My last tool to free more memory for the apps to run faster, is one of the Memory Cleaner / Booster apps (Memory Pro, Free memory, Memory Doctor,...) which usually increase free memory up to 40MB. Also i use Backgrounder app (installed via Cydia) to override the 4 major apps that probably keeps running in the background when launched consuming memory (Mail, Phone, Safari & iPod) and forcing any launched app to quit when minimized to free memory.