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My review after a few hours of heavy use on my iPhone 3G with iOS 4.1:

Cliff Notes: Phone is the fastest it have ever been, even faster than when it had OS 3.x!!!!


I was very very reluctant to update to 4.1 this morning. My reasoning for doing so was this: It's already unusably slow, and barely able to run anything, so the worst that can happen is it stops working altogether.

Well after I installed 4.1, I reboot the phone and started to use it. Now with 4.0.1, everything was scary slow - e-mail took 30+ seconds to load, web browsing took minutes to load a page and it would freeze often, the iPod took well over a minute to load, etc...

Right now, everything is very very quick. Well, it's an iPhone 3G, so for the hardware it has - it's very quick. Text messages take about 3 seconds to load now, e-mail opens right up, web browsing is a significantly improved. The web browsing is a whole new experience compared to what I been dealing with all summer. The browser loads up in 3-5 seconds, the page doesn't try to automatically reload, browsing webpages is smooth without any freezing, and everything moves without any lagging and very fluid.

The iPod takes about 6-10 seconds to load up fully. Not bad compared to before, when it took 45+ seconds and would crash often when it would try to load.

Text messaging is another very smooth experience after it loads, there is no waiting after the initial application launch.

The camera takes about 15-20 seconds to load and become ready to take a photo. A little better than before, but certainly won't be the best choice if you want to capture something very quickly.

Switching between applications quickly is very quick, applications load within a couple of seconds, and are nothing is crashing or freezing.

The whole UI experience is much much more fluid than before. Applications load, Mail launches quickly, text messages can be sent quickly, typing text is instantaneous without any sign of lag, all of the buttons respond the first time you press then and actually do what they were programmed to do.

All of the horrible nightmares that came to the iPhone 3G have been completely erased with this new iOS 4.1 update. I am going to say that my phone now is actually FASTER than when it had iOS 3.x on it.

If you have an iPhone 3G and your phone is a disaster with iOS 4.0.x, I highly highly recommend the upgrade to 4.1. It was most certainly worth the cost of losing my jailbreak and all the applications I had when downloaded when it was jailbroken.
 
My wife's phone is still on 3.1.2, while mine has just been updated to 4.1.0. From what I can tell, it is QUITE a bit faster. When I was on 4.0.2, it was a dog. Hard to type things in, and it was much slower than my wife's phone. Now, I think my phone is a tad quicker, a bit snappier than hers.

Text load ups quicker, it goes to the web quicker, and most of the main apps seem to come up faster on mine now. Settings, however, comes up quicker on hers, less than a second, but still quicker.

Gonna update hers too. Have been hesitant since it was dropped in water and we are just happy it works, but it's been up and running for over a week now, so I think it should be fine.
 
I am extremely happy with the 4.1 on my 3G. I really saw a huge difference! Most of the time, when I was writing messages in Whatsapp, the letters would pop up but not the text (you see what I mean).
Anyway, now it's finished! It's really fast! I was so pissed that I wanted to buy the iPhone 4. Now I can wait one more year and get the iPhone 5.
 
Installed it in about 45 minutes on my 3G, which has choked badly on iOS 4.01. Now is very snappy switching to each app and responding to finger touches in an instant. Not 4G speed but back to iOS 3.1 speed.
However, some apps are still a bit slower than with iOS 3.1. Will add more findings if I find some bugs.
Very happy nevertheless.
Jay

Which apps are slower?
 
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