Apple Inc.'s iPhone 4S is set to face stiff competition from the world's thinnest smartphone, Motorola Droid RAZR, and the first Android 4.0 Ice Cream Sandwich-powered smartphone, Samsung Galaxy Nexus.

The iPhone 4S, which hit the stores last Friday, has come after months of speculation about the imagined iPhone 5. Apple received an overwhelming response from all around the world for iPhone 4S.

Apple said it has sold 4 million units of the iPhone 4S during the opening weekend. The Apple smartphone comes in either black or white and features a 1GHz dual-core ARM Cortex-A9 processor, PowerVR SGX543MP2 GPU, an Apple A5 chipset, an 8-megapixel LED-flash camera with 1080p HD video recording and a secondary VGA front-facing camera for video chat.

The iPhone 4S has a 3.5-inch TFT Retina multi-touch display and is loaded with Apple's latest operating system, iOS 5. In addition, the phone comes with alternating antennae for better call reception, CDMA and GSM support, a personal assistant called Siri, iCloud and Bluetooth 4.0 wireless technology.

Google and Samsung Wednesday unveiled the Galaxy Nexus phone running on Ice Cream Sandwich, the newest version of Android, at an event in Hong Kong. Galaxy Nexus was scheduled to be launched last week, but was postponed possibly as a tribute to the late Apple co-founder, Steve Jobs.

Galaxy Nexus was also known as Samsung Google Nexus Prime, Samsung Google Galaxy Nexus I9250, Samsung Google Nexus 3, and Samsung Google Nexus 4G.

Galaxy Nexus, the first LTE-enabled smartphone to feature Ice Cream Sandwich, is adorned with dual-core 1.2GHz Cortex-A9 CPU, TI OMAP 4460 chipset, 4.65-inch high-definition Super AMOLED display, 1 GB of RAM, 16 or 32 GB of internal memory, NFC, 4G LTE support, 5-megapixel rear-facing camera with 1080p video capture and 1.3-megapixel front-facing camera for video calls.

On the other hand, Motorola on Tuesday unveiled Droid RAZR, which is claimed to be the world's thinnest smartphone with a mere 7.1mm thickness. Droid RAZR, which runs on Android 2.3.5 Gingerbread OS, comes with a syncing system called MotoCast, which, according to Motorola Mobility President Sanjay Jha, is the phone's most important feature.

Droid RAZR is adorned with 1.2 GHz dual-core Cortex-A9 CPU, PowerVR SGX540 GPU, TI OMAP 4430 chipset, 4.3-inch qHD Super AMOLED display, 1GB RAM, 4G LTE support, 8-megapixel autofocus LED flash rear-facing camera with 1080p video capture, secondary 1.3-megapixel front-facing camera for video chat, 16GB internal storage and 16GB microSD external card pre-installed (expandable up to 32GB).

Let's look at the specifications of Apple iPhone 4S, Samsung Galaxy Nexus and Motorola Droid RAZR.

Operating System: Droid RAZR runs on Android 2.3.5 Gingerbread OS while Apple's iPhone 4S runs on the newest iOS 5 that comes with 200 new features that will include an improved Notifications System, Newsstand and iMessage. RAZR will come with a host of new software perks. The MotoCast app will allow users to share content, much like cloud computing, between computers and smartphones via Wi-Fi.

On the other hand, Galaxy Nexus will run on the latest version of Google Inc.'s smartphone operating system, Android 4.0 Ice Cream Sandwich, which is a combination of Gingerbread and Honeycomb in one unit. Android Head of Engineering Mike Claren announced that the new OS is Google's most ambitious release to date.

The newest features arriving with Android 4.0 include widgets in a new tab, a customizable launcher, Gmail with offline search with a two-line preview and new action bar at the bottom, better voice integration, improved copy and paste and a new tabbed Web browser that allows up to 16 tabs.

Size: Droid RAZR will come in 130.7 x 68.9 x 7.1 mm dimension and weighs 127 grams, while iPhone 4S comes with 115.2 x 58.6 x 9.3 mm and weighs 140 grams. On the other hand, Galaxy Nexus will come in 135.5 x 67.94 x 8.94 mm dimension and weighs 135 grams.

Display: Droid RAZR will come with a 4.3-inch qHD screen paired with Super AMOLED touchscreen that may give a resolution of 960 x 540 pixels with about 256 ppi pixel density. iPhone 4S, when compared, has the same 3.5-inch TFT Retina multi-touch display that may give a resolution of 960 x 640 pixels at 326 ppi density.

On the other hand, Galaxy Nexus touts a 4.65-inch high-definition Super AMOLED display that may give a resolution of 1280 x 720 pixels with about 316 ppi pixel density.

Processor: Droid RAZR will feature 1.2 GHz dual-core Cortex-A9 CPU, PowerVR SGX540 GPU, TI OMAP 4460 chipset with 1GB RAM. iPhone 4S, which comes in an A5 chipset, is powered by 1GHz dual-core ARM Cortex-A9 CPU, PowerVR SGX543MP2 GPU. On the other hand, Galaxy Nexus will feature 1.2GHz dual-core Cortex-A9 CPU, TI OMAP 4460 chipset with 1GB RAM.

Camera: Both Droid RAZR and iPhone 4S sport a rear-facing 8-megapixel camera with 1080p HD video capture capability. On the other hand, Galaxy Nexus will sport a 5-megapixel rear-facing camera with 1080p video capture.

For video calls, Galaxy Nexus will sport a 1.3-megapixel front-facing camera while iPhone 4S comes with a VGA one. But Droid RAZR will sport a secondary 2-megapixel camera that can record videos at 720p.

Storage: iPhone 4S has fixed 16/32/64 GB internal storage, while Galaxy Nexus will have a fixed 16/32 GB internal storage. On the other hand, Droid RAZR will have a fixed 16 GB internal storage and a 16GB microSD external card pre-installed that can be expanded up to 32GB.

3G/4G: Apple iPhone 4S has HSDPA 14.4 Mbps, HSUPA 5.8 Mbps support, and also has CDMA EV-DO Rev. A (800, 1900 MHz) technology. Droid RAZR will come with Rev. A up to 3.1 Mbps, 4G LTE, HSDPA and HSUPA, while Galaxy Nexus will have HSDPA 21 Mbps, HSUPA 5.76 Mbps, and 4G LTE support.

WLAN/Bluetooth/USB: Both Droid RAZR and iPhone 4S has Wi-Fi 802.11 b/g/n and Wi-Fi hotspot, but Droid RAZR also has DLNA. On the other hand, Galaxy Nexus will have Wi-Fi 802.11 a/b/g/n, dual-band, DLNA, Wi-Fi hotspot.

Galaxy Nexus will have Bluetooth 3.0 version with A2DP along with microUSB 2.0 version. Both iPhone 4S and Droid RAZR comes with advanced Bluetooth version 4.0. iPhone 4S comes with A2DP along with USB version 2.0, but Droid RAZR will come with LE+EDR along with microUSB version 2.0.

Battery: Motorola Droid RAZR has standard 1780 mAh battery offering talk time of up to 12.3 hours and standby time of 204 hours. The Apple smartphone has a Li-Po 1420 mAh battery, with 8 hours of talk time on 3G networks, up to 14 hours on 2G networks (GSM) and a standby time of 200 hours. On the other hand, Galaxy Nexus will come with a standard 1750 mAh battery.

Pricing: Droid RAZR will be available on Verizon in early November at $299.99, with a two-year contract. On the other hand, Galaxy Nexus will hit the stores in November in the U.S., Europe and Asia (including China and Japan) and as far as the pricing goes, nothing has been announced yet.

With a two-year contract, iPhone 4S costs $199 for the 16GB model, $299 for the 32GB model and $399 for the 64GB model. Apple-listed prices for a contract-free phone in the United States are $649 for the 16GB model, $749 for 32GB and $849 for the 64GB.

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