As with each new iPhone iOS release, features get added and adjusted, but the latest incarnation, iOS4, might be too much for your 3G.

We’ve seen it with our own eyes and had a number of comments from people making stiff complaints about the iPhone 3G’s performance some branding it ‘practically unusable’.

The slower processor speed of the 3G is partly to blame but the big issue here really is the actual code of iOS4 which is designed to maximise the use of everyones processor, although we can’t personally see why you need an increase in processor usage for a different dock image and a set of folders.

One user has already reported that she’s jumping ship and downgrading the software back to OS3 and many others appear to be following suit, including me. One of the biggest heartaches is accessing built in applications like mail and settings. In one example a user needed to connect their phone to a bluetooth headset, and totalled up almost 2 minutes getting into the panel. I was able to replicate this on my own iPhone 3G and whilst I didn’t top the two minute mark, I certainly came close.

The general feeling here is if you have not already upgraded to iOS4, then don’t. It’s simply not worth it on the 3G.

The 3Gs on the other hand has also seen major slowdowns as a result of iOS4, although not as dramatic. The accessibility functions on my own 3GS were slow, choppy and failing to render text correctly or speak it aloud.

Only time will tell if the 3G and 3Gs will see another update that cures the speed issues, but for now, 3G owners will want to skip, 3GS users should be fine unless they want to use something system intensive like accessibility.