The iPhone 4 is no small thing to review. As most readers of Engadget are well aware, in the gadget world a new piece of Apple hardware is a major event, preceded by rumors, speculation, an over-the-top announcement, and finally days, weeks, or months of anticipation from an ever-widening fan base. The iPhone 4 is certainly no exception -- in fact, it may be Apple's most successful launch yet, despite some bumps on the road.The devices reduced size is primarily due to the antennas being placed externally.
The iPhone 4 runs Apple's iOS operating system, the same operating system as used on previous iPhones, the iPad, and the iPod Touch. It is primarily controlled by a user's fingertips on the multi-touch display, which is sensitive to fingertip contact. Without modification, the iPhone restricts users from running any software that is not explicitly approved by Apple and distributed via its App Store.
The most noticeable difference between the iPhone 4 and its predecessors is the new design, which incorporates a stainless steel frame that acts as the device's antenna. The internal components of the device are situated between two panels of chemically strengthened aluminosilicate glass.
It has an Apple A4 processor and 512 MB of eDRAM, twice that of its predecessor and four times that of the original iPhone. Its 3.5 inches (89 mm) LED backlit liquid crystal display with an increased 960-by-640 pixel resolution is marketed as the "Retina Display". Many iPhone 4 buyers have reported signal reduction when the phone is held in certain ways, especially in the left hand, as the antenna problem is in the bottom left corner of the phone's side casing. The company has offered customers a free case until September 30, 2010, or a refund within 30 days of purchase.
The iPhone 4 is structured around a stainless steel frame which both acts as the primary structure for the device, and additionally acts as the iPhone 4's antennae. The stainless steel enclosure features three slits that divide the band into three sections; the left section of band acts as the Bluetooth, Wi-Fi, and GPS antenna, and the right and lower bands sections act as the antenna for GSM and UMTS connectivity. There is some debate as to whether or not this causes issues with signal strength and availability. The act of touching the gap between the two antennas with an un-gloved hand potentially bridges these two separate antennas, leading to poor signal reception.
The main upgrade of the iPhone 3G from the original iPhone was the 3G chip which brought faster download speeds. The main upgrade of the iPhone 3GS from the iPhone 3G was the CPU speed increase and the video-taking capability. All of those were nice upgrades. But again, the iPhone 4 offers much more from a hardware perspective. And that makes it worth the upgrade from an older iPhone, as well as worth an outright purchase if you’re new to the platform.
The iPhone 4, which uses Apple’s A4 chip just like the iPad, is definitely faster than the iPhone 3GS. However, the most part, it’s not noticeably faster in the same way that the iPhone 3GS was noticeably faster than the iPhone 3G. But it is in some cases, such as photo manipulation. One of my favorite apps is one called CameraBag (you can find it here for $1.99). On the iPhone 3GS, it can take several seconds to apply various filters to pictures in this app. On the iPhone 4, the same tasks take about a second.(via TechCrunch)