iPhone EDGE 2.0.1
Pre Upgrade
I was also getting the terrible long backups so before I did the upgrade I deleted all of my emails, all of my SMS and removed old notes and unwanted photos. I also cleared out the cache of safari completely, and the history in youtube.
Doing this improved the speed of the backup immensely (I only have a GB of music on the phone but also have about 32 apps). Was much much faster than before.
Post Upgrade
Once the backup was completed I upgraded to 2.0.1. First impressions were quite good. The OS does feel a bit quicker in various areas.
Down to the testing!!
Did my typical, many applications opening and closing test. Various app store ones such as Aurora Feint (good app to test with as its heavy) and other smaller apps rapid fire open close open close switching among them. On 2.0 this killed my iPhone every time without fail. Resulting in a complete reboot of the iPhone. On 2.0.1 so far I have not managed to kill it so good signs there of improvement.
Update: Just did the test again, really went for it this time, and the iPhone handled it pretty much perfectly, hopefully will stay this way when I add more apps.
The biggie: Contact and SMS lag. It is unfortunately still there. So far from what I have tested it looks as though it wont be as prominent a problem in contacts. Once contacts has managed to get its self scrolling, contact selection is definitely faster although it still needs improving. It is still to easy to make the iPhone keyboard lag in SMS. I have managed to simulate it 5 or 6 times now. That to me shows no improvement especially since my SMS app has been completely cleared of all the messages so that cannot be the problem. Its a shame because in general the update seems a pretty good one.
Safari: To be honest seems pretty much the same, I have found it a good improvement in 2.0 from 1.1.4 (1.1.4 has been by far my favorite firmware as for me it was amazing). Page rendering and two finger zoom rendering maybe a tad faster.
Settings: Scrolling is definitely less choppy. Thats about all I can say!!
Note: All of the tests were done in a situation in which the signal drops out and comes back again frequently. Its not an iPhone problem as other phones on the same network (o2) in my flat, this also happens to them as well due to bad signal. The point I am getting to is that in the past I have noticed that this can affect the iPhone and cause it to have difficulties, slowdowns and crashes. So this again is a good sign as to stability improvements in this firmware.
Hopefully the next update finally sorts the contacts and most definitely fixes the SMS app as that really needs close attention. Other than that a reasonably happy camper here
