3G AT&T internet is slow

[kraziebone]

I have an iPhone 4 with 4.2.1 and my 3G internet speed has been extremely slow but my WiFi speeds are normal. I have tried just about everything and I cannot figure it out. Here is what I have done:
1) restored it 4 different times.
2) 1st jailbroke using greenpois0n and then when that didn't work restored it again with a custom firmware using pwnage tool and then when that didn't work I used snowbreeze custom firmware and then rejailbroke with greenpois0n (I want to keep my baseband at 01.15.00)
2) reset network settings every time I have jailbroke it
3) I did not use a backup that I had on file on my computer when I last restored it to see if it was a corrupted backup, no luck

I cannot figure this out. I will restore it and it will seem to work for about a day and a half and then the 3G just gets ridiculously slow. It will take up to 5 minutes to load a single web page. Any help would be greatly appreciated.

[i.Annie]

You obviously haven't had Verizon to know what slow 3G is lol. On a serious note, if a clean restore doesn't fix the problem, there isn't much you can do. Call AT&T and ask, they'll usually check your area and see if it's an issue with the towers. I had a problem like this once and they eventually resolved it somehow (don't know what they did but they sent someone out to check out the nearby tower, so they claimed).

It's likely the carrier issue not your phone.