What are all the differences between the iPhone 4 and the iPhone 3GS?

With even a quick glance, major differences between the iPhone 4 models -- the iPhone 4 (GSM) and iPhone 4 (CDMA) -- and the iPhone 3GS, the previously released iPhone, are readily apparent. Apple considers the iPhone 4 to be the "biggest leap since the original iPhone," and it certainly has a number of major changes that warrant detailed evaluation.

External Differences

The iPhone 4 (GSM model on the left) uses an entirely new all stainless steel body design with sharper, more angular lines and a thin "metal band" that wraps around the sides of the phone. This metal band has integrated mobile and data antennas and was reportedly designed to improve reception compared to earlier iPhone models.

The iPhone 4 has a high-resolution 960x640 at 326 ppi 3.5", IPS, LED-backlit display with an 800:1 contrast ratio that Apple refers to as a "retina display."

The company uses this name because 326 pixels per inch (ppi) is said to exceed the 300 ppi that the human eye is able to differentiate individual pixels from twelve inches away. As a result, content on the display should look more like that in a printed book than on a computer screen.

Although some have taken Apple to task for this claim, and instead have stated a more accurate "retina display" calculation would be 477 ppi -- and others have defended the company's claim as well -- magazines are commonly printed at 300 dpi and the iPhone 4 display is decidedly high-quality for a mobile device.

The iPhone 4 has a chemically hardened "aluminosilcate" glass front over both the display and although it was originally announced on June 7, 2010, with a white or black frame and a chemically hardened white or black glass back as well, the white model had numerous delays and did not ship until April 28, 2011.

By contrast, the iPhone 3GS (left) uses a largely plastic design with a more prominent metal "lip" around the edge of the front and has a black or white plastic back. iPhone 3GS models with a white plastic back -- discontinued configurations with 16 GB or 32 GB of storage -- still have a black front.

The back of the iPhone 4 and iPhone 3GS are considerably different beyond material -- glass and plastic, respectively -- as the iPhone 4 is flat and the iPhone 3GS is rounded and tapered toward the edges. The iPhone 4 is a great deal thinner as well, 0.37 inches (9.3 mm) compared to 0.48 inches (12.3 mm) for its predecessor. If you're keeping score, the iPhone 4 is reported to weigh 2 grams more than the iPhone 3GS but this is unlikely to be perceptible.

The display on the iPhone 3GS also is 3.5 inches but is only 320x480 at 163 ppi with a 200:1 contrast ratio, noticeably lower resolution than the 960x640 at 326 ppi display on the iPhone 4. Both the iPhone 3GS and iPhone 4 have "oleophobic" oil repellent coatings on the front, but the iPhone 4 has the same coating on the glass back as well.

Identification Differences

One simple way to identify the iPhone 3GS and iPhone 4 models, as well as all other iPhone models, is by the model number printed in small type on the back of the phone.

The standard iPhone 3GS is model number A1303, the mainland China-only iPhone 3GS without Wi-Fi is A1325, the GSM-equipped iPhone 4 is A1332, and the CDMA-equipped iPhone 4 is A1349. The subsequently introduced model iPhone 4S -- which looks effectively identical to the iPhone 4 models -- has model number A1387 on the back.

Everyi.com's Ultimate iLookup feature also can identify these iPhone models by EMC number, order number (referred to as "model" in software), and the last three or four characters of their serial numbers as well (the last three characters for devices with an eleven character serial number and the last four characters for devices with a twelve character serial number).

Camera Differences

The audio visual capabilities of the iPhone 4 and iPhone 3GS are a major point of differentiation. The iPhone 4 has dual cameras -- a 5 megapixel HD video/still camera (720p at 30 FPS) with a "backside illuminated sensor," a 5X digital zoom, and an LED flash on the rear and a VGA quality video/still camera on the front designed for video conferencing over a Wi-Fi network with Apple's included "FaceTime" application. The iPhone 4 has dual noise-canceling microphones as well.

The iPhone 3GS, by comparison, has a single 3.0 megapixel camera with VGA video recording at 30 FPS and a single microphone. Both models have autofocus, macro, and white balance support, and "tap to focus" features although the iPhone 4 is reported to have a superior macro mode. The iPhone 3GS has basic "video editing" capabilities -- you can cut the beginning and end of a clip "in camera" -- but the iPhone 4 goes much further. When paired with a new iMovie application -- available for purchase separately for US$4.99 -- the iPhone 4 supports a variety of more full featured video editing and effects capabilities.

Internal Differences

Internally, the iPhone 4 and iPhone 3GS models are considerably different as well. The iPhone 4 models have an "Apple A4" processor of unspecified speed and 512 MB of RAM and the iPhone 3GS has an ARM Cortex A8 processor running at 600 MHz (downclocked from 800 MHz) and 256 MB of RAM.

The iPhone 3GS supports 3G UMTS/HSDPA networks and the iPhone 4 (GSM) supports UMTS/HSDPA/HSUPA networks for compatibility with more cellular carriers worldwide. Both the iPhone 3GS and the GSM-equipped iPhone 4 support the slower GSM/EDGE network as well. The iPhone 4 (CDMA), on the other hand, instead supports CDMA (EV-DO, Rev. A, 800 MHz, 1900 MHz).

Both the iPhone 3GS and the iPhone 4 models support Bluetooth 2.1+EDR as well as Wi-Fi, but the iPhone 3GS supports 802.11b/g and the iPhone 4 models support the same 802.11b/g in addition to the 2.4 GHz frequency of 802.11n. The iPhone 4 (GSM) uses a Micro SIM whereas the iPhone 3GS uses a Mini SIM (more commonly called simply a SIM card), and the iPhone 4 (CDMA) has no SIM card at all.

Both models include an accelerometer, proximity sensors, an ambient light sensor, A-GPS, and a digital compass but the iPhone 4 adds a three-axis gyroscope for more 3D gaming options. As originally shipped, the iPhone 3GS had 16 GB or 32 GB of storage, and the iPhone 4 ships with the same capacity options, but the iPhone 3GS was "downgraded" to a mere 8 GB of storage -- with a lower price tag -- when the GSM-equipped iPhone 4 was released.

Battery Life Differences

Battery life has been increased on the iPhone 4 when compared to the iPhone 3GS too. Apple reports that audio playback has been increased to 40 hours from 30, talk time on 2G to 14 hours from 12 (the CDMA-equipped iPhone 4 does not support 2G), talk time on 3G to 7 hours from 5, Internet use on Wi-Fi to 10 hours from 9, and internet use on 3G to 6 hours from 5. Each provides an estimated 10 hours of video playback and 300 hours of standby time.

Pricing Differences

Pricing in the United States for the GSM-equipped iPhone 4 was the same as it was for the iPhone 3GS when it was released -- US$199 for the entry-level model and US$299 for the high-end model, offered with 16 GB and 32 GB of storage, respectively, with a two-year AT&T contract. The CDMA-equipped iPhone 4, likewise, was available for US$199 and US$299, but on Verizon in the US also with a two-year contract.

On June 7, 2010, Apple introduced an entry-level configuration of the iPhone 3GS alongside the iPhone 4 and this configuration was offered with 8 GB of storage for US$99 with a two-year agreement.

On October 4, 2011, upon introducing the iPhone 4S, Apple introduced an 8 GB configuration of the iPhone 4 GSM and CDMA models for US$99 on either AT&T, Verizon or Sprint with a two-year agreement. Apple simultaneously dropped the price of the 8 GB iPhone 3GS to free, still with a two-year contract.

Comparison Chart

For your convenience, the main differences between the iPhone 4 models and the iPhone 3GS also have been summarized below:

	iPhone 3GS	iPhone 4
Processor Speed:	600 MHz	1 GHz*
Processor Type:	ARM Cortex A8	Apple A4
Standard RAM:	256 MB	512 MB
Standard Storage:	8 GB** (16, 32 GB)	8 GB*** (16, 32 GB)
Display Resolution:	480x320	960x640
Display PPI:	163 ppi	326 ppi
Contrast Ratio:	200:1	800:1
Oleophobic Coating:	Front	Front & Back
Housing Material:	Glass & Plastic	Glass & Steel
Front Color:	Black**	Black or White
Back Color:	Black or White**	Black or White
Camera Megapixels:	3.0 Megapixels	5.0 Megapixels
Video Recording:	VGA	720p & VGA
LED Light/Flash:	No	Yes
Dual Cameras:	No	Yes
Dual Microphones:	No	Yes
GSM/EDGE:	Yes	Yes/No††
UMTS:	Yes	Yes
HSDPA:	Yes	Yes/No††
HSUPA:	No	Yes/No††
Wi-Fi:	802.11b/g	802.11b/g/n
Bluetooth:	2.1+EDR	2.1+EDR
Digital Compass:	Yes	Yes
A-GPS:	Yes	Yes
Gyroscope:	No	3-axis
Talk Time (3G):	5 Hours	7 Hours
Talk Time (2G):	12 Hours	14 Hours††
Battery Life (Web - 3G):	5 Hours	6 Hours
Battery Life (Web - Wi-Fi):	9 Hours	10 Hours
Battery Life (Music):	30 Hours	40 Hours
Battery Life (Video):	10 Hours	10 Hours
Standby Time:	300 Hours	300 Hours
SIM Card:	Mini	Micro
OS Support:	iOS 4	iOS 4
Dimensions (Inches):	4.5 x 2.4 x 0.48	4.5 x 2.31 x 0.37
Weight:	4.8 oz. (135 g)	4.8 oz. (137 g)
Model No:	A1303/A1325	A1332/A1349
Price (As Introduced):	US$199, US$299†	US$199, US$299§
Price (Current):	US$0†	US$99§

* Apple provides no official information regarding technical details for the iPhone 4 and the clockspeed is officially unreported. However, multiple third-parties have speculated that it has a variable speed processor with a maximum clockspeed of 1 GHz.

** The iPhone 3GS originally was offered with a black front and either a black or white plastic back and 16 GB or 32 GB of storage. Starting on June 7, 2010, it only was offered with a black front and a black plastic back and 8 GB of storage.

*** The iPhone 4 originally was offered with 16 GB or 32 GB of storage. On October 4, 2011, Apple introduced an 8 GB configuration of the iPhone 4 GSM and CDMA models for US$99 on either AT&T, Verizon or Sprint with a two-year agreement.

† On June 7, 2010, Apple discontinued the 16 GB and 32 GB configurations of the iPhone 3GS that were US$199 and US$299 and introduced an 8 GB configuration for US$99 for "qualified" AT&T Wireless customers with a two-year contract. On October 4, 2011, Apple dropped the price of the iPhone 3GS to free, again, with a two-year contract.

†† The iPhone 4 (CDMA) instead supports CDMA (EV-DO, Rev. A, 800 MHz, 1900 MHz).

§ On October 4, 2011, Apple discontinued the 16 GB and 32 GB configurations of the iPhone 4 that were US$199 and US$299 and introduced an 8 GB configuration of the iPhone 4 GSM and CDMA models for US$99 on either AT&T, Verizon or Sprint with a two-year agreement.

Comparison Summary

Ultimately, which iPhone to get is your decision, but as most of the cost is tied to the expensive plan in many countries rather than the hardware itself, typically only those on the tightest of budgets -- and those on tight budgets should not purchase an iPhone at all -- should consider the iPhone 3GS.

However, those who have an unlocked iPhone and who need to switch between carriers frequently when traveling internationally may find the GSM-equipped iPhone 4 Micro SIM inconvenient and the modest selection of supported countries for the CDMA-equipped iPhone 4 unacceptable and instead find the iPhone 3GS well worth consideration. Nevertheless, for most users, an iPhone 4 model (or the more recently introduced iPhone 4S) is a better choice.

Also see:

• What are all the differences between the iPhone 4S and the iPhone 4? Which one is best for my needs?
• What are all the differences between the iPhone 4 (GSM) and the iPhone 4 (CDMA)?
• What are the main differences between each iPhone -- the iPhone 4S, the iPhone 4, iPhone 3GS, iPhone 3G and the original iPhone? How can each be identified quickly?