iPhone 3G Performance – OS 3.1.3 vs iOS 4

Oh boy. This is one laggy beast. iOS 4 is slow in most things when compared to OS 3.1.3 on an iPhone 3G (non-jailbroken). Although I haven’t noticed that much of a difference in performance as evident from the video, it makes one wonder whether the upgrade to iOS 4 is really worth it or not. You be the judge:

via Daring Fireball

About the Author

Technology enthusiast, Internet addict, photography fan, movie buff, music aficionado.


  1. It seems taking pictures on iPhone 3G iOS 4 is faster than 3.1.3 after the first slow shot. I'd like to see a comparison of multiple shots.

  2. that is 'cuz its pre initialized in the memory. Thus, all subsequent launches will probably be faster.
    That's probably why its worth to upgrade to ios4 as it features outweighs it…

  3. I didn't notice any of this lag.
    There is some lag, sometimes. But not laggy as in the video.

    Taking pictures is as fast or faster as in 3.1.3. The initial lag is because it's the fisrt run. Although I didn't notice any lag on taking pictures even on the first picture.

    I also made a Clean Install and not an upgrade. Maybe that can also help.

    I think iOS 4.0 it's beautifull and the folder system is fantastic! I normaly had 7 to 8 pages with apps. Now I only need one page. Folders are really great and I think worth trying.

    But, if any of these features are relevant for you. Than, you can stay with 3.1.3. But 4.0 is very nice.

  4. I initially had very bad lag, but strangely it mostly went away after I did a full reboot (hold down home & lock until the apple comes up). The only thing I notice now is launching Stanza is slightly slower.

  5. The system apps are fast-task-switching enabled and are memory resident after the first launch.
    There's no initialization time on 3GS and iPhone 4.

    The 3G is very memory constrained (128MB) compared to 3GS (256MB) and iPhone4 (512MB).
    Given that the OS is (roughly) a fixed size, the amount of free memory available to application is increased
    by many times more than the 2-4x would suggest.

    This is also why multi-tasking is turned off. 3G wouldn't have the memory to keep many apps around without constantly booting them out of memory, a poor experience.

    Also why Adobe Flash is denied. Its memory usage compromises multi-tasking.
    Apple would rather use that extra memory to give people features like faster startup time (more apps in the “background”).

  6. After updating I had some major lagg issues. So slow that I could not move between my home vidows, or even unlocking the phone was difficult. After a few restarts it finaly worked. I use a memory monitoring softwarecalled Free Memory, with 3.x version on my 3G I had usually 20-52mb memory free, now after update I have only 2-12MB free while running NO applications at all, just the OS. I regret upgrading already.

  7. Numerous crashes and glacially slow. When I type in a word the first letter expands and then sits there while I type in the rest of the word. Then the first letter jumps into the box and each subsequent letter follows slowly. I have the FreeMemory app also, and as the first responder noted, there is a significant loss of free memory. I used to have around 40 MB free and now lucky to have 12.

  8. Slow. Slow. Slow. That is all I can say. From unlocking the phone too, sending text, reading email and the lists goes on. Apple done it again, upgrade the os4 to make it slow on the 3G so you can upgrade to 3Gs or 4G phone.

  9. Hi, i was just wondering if anyone had noticed a major slow down when using whatsapp messenger? My phone now takes about 20 seconds to even open up texts, the keyboard is laggy as anything. The phone is virtually unusable. Does anyone understand the OS structure enough to comment on whether a clean rebuild would clear up any of these issues? Thanks

  10. First of all, who cares if it speeds up after the first x amount of shots, the iOS4 is so slow it doesn't make the iPhone usable anymore. I have to wait an additional 45 seconds before my texting window opens. This used to open at the touch of a finger; which is what Apple tells us is supposed to happen. The iOS doesn't live up to the hype and it's a piece of crap.

  11. this isnt bad compared to mine, for some reason it’s ridiculously slow compared to other ios 4.0+ iphone 3g devices let alone anything else, I very nearly resorted to using my ipod touch 1g and Samsung U900 the other day as its p*ssing me off

Leave a comment