Here's a slide from AT&T showing the percentage of dropped calls on their 3G network: You can find this slide on page 11 of this document: http://www.att.com/Investor/Financial/Earning_Info/docs/4Q_09_slide_c.pdf And here's a slide from Jobs' iPhone 4 presentation: From the AT&T slide we can surmise that the average percentage of dropped calls on AT&T's 3G network is around 1%. Let us first assume that the percentage of dropped calls for the iPhone 3GS is about the same as the average of all phones on AT&T's network. That means the 3GS drops 1 call per 100. Now, the Apple slide says the iPhone 4 drops <1 more call per 100 than the 3GS. Let's first use the maximum, 1 more per 100. That would mean the iPhone 4 drops approximately 2 calls per 100. That's an 100% increase in dropped calls over the 3GS. Of course, it may be argued that the above made assumptions are faulty. Let's relax them some. What is <1? I think it could be as small as 0.5. Any less than that, it would be silly for Apple to round up and make themselves look bad. And what about the 3GS' drop rate? Maybe 3GS has worse reception than the average phone on AT&T's network? Could the 3GS have 10 times worse reception than the average phone on AT&T's network? That's pretty harsh, but let's go with that. That means the 3GS drops 10 calls per 100, while the iPhone 4 drops 10.5 calls per 100. That's still a 5% increase in dropped calls, even when we are being so harsh on the 3GS, still a pretty significant number. If we are less ridiculous about the 3GS' performance, and say it performs 2x worse than the average AT&T phone, Then it's 2 dropped call for the 3GS versus 2.5 dropped call for the iPhone 4, a 25% increase, which is still huge.