I upgraded my wife's iPhone 3GS to iOS 5.0.1 and now basic tasks like opening apps like Texts/Phone dialer are now slower than before. I understand the 3GS is 2 years old, but just being able to type Text messages fluidly is a super basic task that a 600Mhz processor should handle just fine (as it did on iOS 4.x and 3.x). If not, Apple shouldn't be pushing and advertising iOS 5.x for 3GS's.

Anyway, what iOS version do you recommend I revert to?

Although the iPhone is no longer jailbroken, I recall backing up the "SHSH blobs" to Cydia when it was jailbroken. So I should be able to revert to builds no longer signed by Apple.

  • I am using iOS 5 on an iPhone 3GS. No speed issues, no crashes, and of course better features than the older versions of iOS. The only downside I've found so far (and it might be the hardware), is when the battery life drops under 10% I have a 50% chance of my iPhone switching off. But it's minor to the goodies iOS 5 has to offer, which I believe will be the last OS upgrade for this generation of iPhone.
    – isioutis
    Commented Jan 5, 2012 at 8:37
  • 1
    So, is your wife's 3Gs Jailbroken currently or not? Commented Jan 5, 2012 at 10:45
  • Not jailbroken since the iOS 4.3.3 -> 5.0 upgrade ... Commented Jan 5, 2012 at 17:02
  • Disable pin locking - this will make a difference.
    – mspasov
    Commented Nov 14, 2012 at 10:08

4 Answers 4


Ok, so after some quick googling and reading some Apple forums, it looks like iCloud (in iOS 5.x) isn't ready for prime time. I've done the following and now iOS 5.x seems a lot snappier.

  1. Disabled iCloud everywhere (Settings -> iCloud)

    Disable all apps then Scroll down and hit "Storage and Backup" and disable iCloud backups. If you really want to go strong, just delete your iCloud account setting (on your phone, Settings -> iCloud -> scroll to bottom)

  2. Disabled sending data to Apple (Settings -> General -> About -> Diagnostic & Usage -> "Don't send")

  3. Minimized Location Services (Settings -> Location services)

    I kept it ON globally, but disabled it for certain Apps Most importantly, disabled it for "Diagnostic & Usage" as well as "Location based iAds" (Settings -> Location services -> Scroll to bottom -> System Services)

  4. Disabled notifications for the calendar (Settings -> Notification)

    I also removed notifications for many other apps that had added themselves ... However, I suspect this is fixed in iOS 5.0.1 under their "Battery issue fixed" patch. Earlier, Calendar notifications would hang causing CPU to be stuck 100%, draining the battery and leaving little CPU for other items.

Also, there are two apps, SysStatsMon and System Status. Both are good tools to see CPU usage on your iOS device. About 5+ seconds after launching them under normal circumstances, your CPU should be in the 5-15% range.

  • +1 for an answer containing actual, empirical information. :)
    – Dan J
    Commented Jan 5, 2012 at 20:03
  • That's a lot of information.
    – Jash Jacob
    Commented May 17, 2013 at 5:17

My Girlfriend has my old 3GS running on iOS5 and there is no speed issues. So not a problem with the OS.

However if you are really not comfortable with it, use iOS4. Although that was made for the iPhone 4 it worked very well with the iPhone 3GS without speed issues.


The latest is the fastest. So 5.0.1.

  • Unfortunately, this is not always the case. I remember my wife's 3G got slower and slower with every single update, to the point where the camera was basically unusable.
    – John B
    Commented Jan 11, 2012 at 17:55
  • Hate to break it to ya, but I doubt that updating was the reason for it being slower. Although, I could be wrong.
    – Dustin L.
    Commented Jan 12, 2012 at 23:34
  • I'm almost 100% it was the reason. Fast camera = slow camera after update. Pretty straightforward result. We even tried doing factory restores with the same speed issues.
    – John B
    Commented Jan 13, 2012 at 13:36

iOS 4.2.1 is the fastest for iPhone 3GS. But many apps not support iOS 4 anymore. iOS 6 is faster than iOS 5 on 3GS – but big apps like Flipboard may be slow due memory limit on 3GS.

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