3G iOS4 resulting in sluggish performance and horribly slow calendar

Same problem for me.

After updating to 4.01 I tried to restore my iPhone 3G as "new iPhone". Nothing better !

Hope the number of "page views" in this thread (and in plenty of other forums and blogs) will stimulate Apple to solve the problems via an official downgrade option or via a new update.

But, seems that mister Jobs only counts the phone calls to Apple Care... Too bad !

Unfortunately, my phone seems to get worse and worse after 4.0. It now reboots and crashes consistently, and for 4 hours yesterday (pre-upgrade) and all morning today (with 4.0.1) registers as "No Service." It was working smoothly (and faster) this morning, but now any non-Apple App crashes after the intro screen, and I am occasionally getting a post-reboot "Reconnect to iTunes" screen.

Apple - please help - I use this for work!

Yep...also experienced same phenomenon. Iphone 3G totally messed up with IOS4. Just stay with 3.1.3... IOS 4 is not usable at all with the 3G. I wonder why Apple provided upgrade for 3G.

No background ⚠ in springboard, no multitasking...whats the effort then? The extremely poor performance? Upgrading a 3G to IOS4 is like putting Win7 onto a pentumII. Somehow it might work but ****....where's the usability? I am really fed up. Can't even cancel phonecalls cos i got a Lock-Screen during call. The "app folders/email-structure" is not worth all the trouble...

I, for my part, perform a downgrade to 3.1.3 and stay with it. Probably will go for a iPhone4 once the hardware issue (antennagate) is fixed.

i found everything was sluggish (messeges, camera, calender,settings & a lot of programs) for both iOS4 & 4.0.1 - so downgraded back to 3.1.3 - lost everything - so if you do do it, back it all up. but now everything works at a reasonable pace again.

Another hacked off user here. 3G upgraded to 4.0 looked promising but then slowed down. My wife uses the phone and got annoyed by the battery drain (I'd been getting that with 3.x anyway), then got even more annoyed by the Calendar app doing its "wait, load, show entries, blank out entries, load in from MobileMe again, wait, show updated entries" thing.

Upgraded to 4.01 (via a restore as new Phone, then restore from backup in iTunes) and things seemed well, until my wife used Calendar app again.

Will try turning off Spotlight on the 3G and see what that does for performance. Have been hearing good things about that from Lifehacker and others. Will post here if it improves anything.

In happier news my iPhone 4 has so far functioned remarkably well, and I've yet to reproduce the "grip of death" the media are so frenzied about!

Is there anyone out there in Apple who is going to make the Calendar app go at a reasonable speed under OS4 on an iPhone 3G? I have four included calendars and it takes between 5 and 10 seconds to restart each time: there appears not to be any caching of the previous state anymore either. the 3G does not have the luxury of keeping more than one app running at once.

For that matter most apps are much slower under OS4. This is not really the best way to encourage us to upgrade to new hardware...