AT&T and Verizon both have 4G LTE....both are exactly the same specs and speed.
AT&T and Verizon use different 3G technologies. AT&T's is far superior than Verizon's or Sprint. AT&T is much faster and can support data/voice multitasking.
The current and latest iPhone 4s is a "3G" phone.
This is not 100% accurate. If one wants to be really technically, neither LTE nor WiMax is true 4G. Verizon/Sprint claim those to be 4G due to the speed that it brings. Because it comes closed to the speed specs documented by 4G.
So when Apple said in their keynote back in Sept that they are not going to say what is 4G and what is not... they said the players (Verizon/Sprint) are calling '4G' if it can acheive a minimal speed performance... than by their definition, iphone 4G with HSDPA+ an do 4G speed too.
'LTE-Advance' is supposed to be 'true 4G'... Sprint is trying to drop WiMax and start migrating to LTE-Advance -- so they say. They claim 'true 4G' technology like LTE-Advance is supposed to be MUCH faster that LTE/WiMax.
Some people would argue that LTE/WiMAX/HSDPA+ are really 3.5G...
T-Mobile's 4G BTW is really HSDPA+ same as iphone 4S; if 4-Mobile can claim HSDPA+ as 4G, than AT&T can say iphone 4S is a 4G phone. =/ In contrast, to say iphone 4S is NOT a true 4G phone is to also say all T-Mobile's 4G phone are also not 4G phones.
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AT&T has the only "4G" iPhone. If they are using the HSPA+ or whatever it is called while the other carriers are using 3G, it's a mute point. Try using AT&T's actual 3G network. There is no way in hell the 4S and 4 are nearly equal on AT&T.
HSDPA+ is supposed to give 14.4MBPS...
At around 6 MBPS, it looks like the iphone 4S is only performing at top HSDPA speeds and not HSDPA+.
If it was really going at HSDPA+ it should hit 11MBPS or higher.
It looks to me both iphone4/4s in this chart were performing more on 3G speeds than actual HSDPA+/4G speeds... which is why they were more or less the same...
So at '3G' speeds and according to this chart, it appears AT&T's 3G network speed are faster than Verizon or Sprint's 3G speed for the iPhone 4S/4...
So it is more apple's to apples errr... 3G versus 3G network... not 4G versus 3G network.