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iPhone Q&A - Updated September 26, 2014

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

Please note that the iPhone 3GS and iPhone 4 both have been discontinued. However, this Q&A has up-to-date iOS support information and is quite useful for anyone buying or selling either of these models on the used market.

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

External Differences

The iPhone 4 (GSM model on the left) uses an entirely different 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 "aluminosilicate" 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

Although it is easy to tell these two devices apart side-by-side, it is easy to mistake either for another iPhone. Consequently, one simple way to externally identify the iPhone 3GS and iPhone 4 models, as well as all other iPhone models, is by the Model Number displayed in small type on the back of each 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 models are A1332, and the CDMA-equipped iPhone 4 is A1349. The subsequently introduced iPhone 4S models -- which look effectively identical to the iPhone 4 models -- are model numbers A1387 and A1431.

If the iPhone will boot, it may be even easier to lookup any of these models by Order Number with's Ultimate iLookup feature or the EveryMac app (available for iOS 5 or later as well as Android). Apple refers to the order number as "Model" in software. To find the "Model" select the "Settings" app and then click General > About > and scroll until the field is visible.'s Ultimate iLookup and the EveryMac app also can identify these iPhone models by EMC Number and their Serial Numbers, as well.

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 whereas the iPhone 4 (GSM) and iPhone 4 (GSM, Revision A) support 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.

iOS Support Differences

Both the iPhone 3GS and iPhone 4 fully support iOS 4 and iOS 5, but only partially support iOS 6. The iPhone 4 also partially supports iOS 7, whereas the iPhone 3GS does not support iOS 7 at all.

For iOS 6, the iPhone 3GS and iPhone 4 models do not support the iOS 6 turn-by-turn navigation, Flyover, or Panorama features. The iPhone 4 models do support the iOS 6 Offline Reading List feature as well as the previously introduced FaceTime feature.

For iOS 7, the iPhone 4 supports all basic functionality -- Control Center, Notification Center, and Multitasking, as well as Safari and iTunes Radio -- in addition to "Filters in Photos" and an assortment of photo functionality that Apple refers to as "Square and video formats and swipe to capture." However, the iPhone 4 does not support AirDrop or Filters in Camera and it still doesn't support Panorama or Siri (although clever hackers have been able to run Siri on the iPhone 4).

The iPhone 4 also is notably slower running iOS 7 than iOS 6 and based on hands-on experience and reader feedback, only would recommend running iOS 7 on this model if you are willing to sacrifice speed for new features and more recent app compatibility. It cannot run iOS 8 or later versions of the iOS at all.

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 the 8 GB iPhone 4 (GSM, Revision A) and an 8 GB configuration of the iPhone 4 (CDMA) 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.

On September 12, 2012, alongside the introduction of the first iPhone 5 models -- the iPhone 5 (GSM/North America), (CDMA), and (GSM/International) -- Apple discontinued the iPhone 3GS and lowered the price of the 8 GB iPhone 4 configurations to free with a two-year contract.

This final 8 GB iPhone 4 configuration was discontinued on September 10, 2013, with the exception of the mainland China market, where it remained available for RMB 2,588 until September 9, 2014.

Comparison Chart

For your convenience, the main differences between the iPhone 4 models and the iPhone 3GS 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
Original iOS: iPhone OS 3.0 iOS 4.0/4.2.3
iOS 4 Support: Complete Complete
iOS 5 Support: Complete Complete
iOS 6 Support: Partial Partial
iOS 7 Support: None Partial
iOS 8 & Later Support: None None
FaceTime Support: No Yes
Siri Support: No No (Hacks Only)
Offline Reading (iOS 6/7): No Yes
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
Intro Price: US$199, US$299† US$199, US$299§

* Apple provides no official information regarding technical details for the iPhone 4 and the clockspeed officially is unreported. However, third-party software analysis has determined 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. From June 7, 2010 until September 12, 2012 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 8 GB configurations of the iPhone 4 GSM and CDMA models.

† 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. This model was discontinued entirely on September 12, 2012.

†† 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. On September 12, 2012, Apple lowered the price to US$0, still locked and with a two-year contract. On September 10, 2013, Apple discontinued the iPhone 4 in most markets and discontinued it entirely on September 9, 2014.

Comparison Summary

Ultimately, the iPhone 4 models are faster and have more RAM, better and dual cameras, faster network support, better battery life, and newer iOS support than the iPhone 3GS. The iPhone 4 design itself -- with both a glass front and back -- can be less durable, though.

Most users would be best off purchasing a newer iPhone model, as neither the iPhone 3GS or iPhone 4 support a modern version of the iOS. However, between the two models, the iPhone 4 is the clear winner. On the used market, the iPhone 4 is quite inexpensive and it remains capable for some uses. Nevertheless, those with more to spend likely would prefer a newer model, though.

Only those on the tightest of budgets, with modest performance expectations, and who are content using older apps and slower mobile data networks, should really consider the iPhone 3GS.

However, those who travel frequently in markets with fairly vintage telecom systems may find the older Mini SIM standard used by the iPhone 3GS an advantage over the Micro SIM that the iPhone 4 (GSM) uses. Furthermore, the modest selection of supported countries for the CDMA iPhone 4 also may be unacceptable. These users still may find the iPhone 3GS worth consideration. Durability and low cost also can be worthwhile for those traveling frequently in areas where damage or theft could be an issue.

iPhone Purchase & Sale Options

There are a large number of places to purchase a used iPhone. However, purchasing from a quality company with extensive iPhone knowledge -- and after sales support -- will provide the best experience and save you money and time, too.

In the US, site sponsor PowerMax has a good selection of used iPhones -- including the iPhone 3GS and iPhone 4 -- available for sale free of sales tax. PowerMax also accepts trade-ins on older iPhones toward the purchase of a newer iPhone or anything else they sell. If you just want money for your old iPhone, site sponsor BuyBackWorld will buy your iPhone 3GS, iPhone 4 or newer iPhone directly for fast cash.

In Southeast Asia, Singapore-based site sponsor PCPRO provides quick money for used iPhone models as well as all other Apple hardware.

Please also see's Ultimate iComparison feature to dynamically compare any iPhone model to any other iPod, iPhone, or iPad.

Also see:

  • What are all the differences between the iPhone 4 and the iPhone 4S? Which one is best for my needs?
  • What are all the differences between the iPhone 4 (GSM) and the iPhone 4 (CDMA)?

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