Wed, 12 Oct 2011 iPhone 4S review

Speedy 4S

Like the iPad 2 before it, the iPhone 4S is powered by an Apple-designed A5 processor. This is a dual-core processor that’s one generation more advanced than the A4 processor that powered the iPhone 4 and the original iPad.

Two processor cores don’t necessarily mean the iPhone 4S is twice as fast as the iPhone 4—that has a lot to do with how efficiently a device’s software can take advantage of spreading the workload across both cores. But the 4S’s upgraded processor definitely provides a large speed boost, akin to the upgrade from the original iPad to the iPad 2.

The results of my general-performance tests showed the iPhone 4S to be roughly twice as fast as the iPhone 4. Apple claims graphics performance on the iPhone 4S has been boosted even more by the graphics component of the A5, with speed gains of as much as 7x. That’s a best-case scenario, but my tests with the GLBench Pro graphics benchmarking app did show enhanced graphics performance. One 3D test sequence played at roughly five times the frame rate of the same scene on the iPhone 4; another was roughly double the frame rate.

Of course, many people won’t be upgrading to the iPhone 4S from the iPhone 4, due to those pesky two-year phone contracts that cell carriers insist on. But a whole lot of people will be upgrading from two-year-old iPhone 3GSes. 3GS users will see an even larger speed increase, of course. The 4S had more than double the score on the GeekBench testing app, and loaded a test webpage in a third of the time.

The only iOS device in existence that can match up—and even beat—the iPhone 4S is the iPad 2. In most of my tests, the iPad 2 was slightly faster than the iPhone 4S. (The original iPad was similarly faster than the iPhone 4, in fact.) Of course, the iPad 2 doesn’t fit in your pocket, unless you have unusually large pockets or are a clown, or both.

Apple claims that talk time on the iPhone 4S’s battery is actually an hour longer than on the iPhone 4, but that Wi-Fi surfing will drain the battery an hour sooner. Apple says that the innards of the iPhone 4S have been entirely redesigned—so many components have changed, there’s no simple explanation for the change in the company’s battery-life claims. It seems clear, though, that some components are more energy efficient than on the iPhone 4 (I’m looking at you, cellular radio) while others eat more power (dual-core A5 processor).

The end result is a phone that offers largely the same battery life as the iPhone 4. However, I didn’t get a chance to run any dedicated battery tests on the iPhone 4S. In general usage, it didn’t seem to run out of battery any faster than my trusty iPhone 4.

A tale of two technologies

When Apple released the Verizon-compatible version of the iPhone 4 in February, the previously-simple iPhone product line got a little more complicated. That’s because Verizon’s network in the U.S. uses a different wireless standard (CDMA) than the networks the iPhone had previously supported, all of which (including AT&T in the U.S.) used the more common GSM wireless standard.

Verizon and Sprint both still use CDMA networks in the United States, but that fact no longer causes a product schism: The iPhone 4S can connect to either CDMA or GSM networks. That’s a big deal for Apple, which no longer has to build two different versions of the same phone, but it’s less dramatic a change for regular users.

That’s primarily because most iPhones are sold as a part of a package deal that includes a two-year contract with a specific wireless carrier. The phone you get as a part of that deal is locked, which is to say it’s tied to the carrier you got it from and can’t easily be moved to a different one.

There is one scenario, however, in which this new phone design becomes a big deal: international travel. Users of iPhones locked to AT&T have always been able to travel internationally, since GSM is a cellular standard that is supported all over the world. Users of the CDMA iPhone 4 (the “Verizon iPhone,” though that model will also now be available from Sprint) couldn’t travel reliably with the phone internationally, since it only supported the CDMA wireless standard, which isn’t that widely used outside of North America and parts of Asia.

With the iPhone 4S, this is no longer a problem. The iPhone 4S can use CDMA when in the U.S., but will switch to GSM when in a country without any CDMA networks. By default you’ll pay Sprint or Verizon’s international roaming rates and use their preferred overseas partners. But Sprint and Verizon will also let you buy and use local pre-paid micro-SIM cards, which offer much more affordable rates for overseas data and voice. It’s a big advantage for Sprint and Verizon. (For more details, check out my story about the iPhone 4S as a “world phone.”)

AT&T does have one clear advantage over the other carriers in the U.S., however: speed. In February I discovered that the Verizon 3G network was more reliable than AT&T’s, but was also noticeably slower. Though many carriers are rolling out 4G networks in the U.S., the iPhone 4S does not support them. (AT&T has been slower at rolling out a 4G network, but it’s got a very fast 3G network—and the iPhone 4S takes advantage.)

As a result, the theoretical maximum 3G download speed of the iPhone 4S is 14.4Mbps, double the 7.2Mbps limit on the iPhone 4. (In contrast, CDMA’s theoretical maximum download speed is 3.1Mbps.) Still, in my tests I couldn’t get download speeds above 4.2Mbps on AT&T’s 3G network in the San Francisco area.