With the iPhone 4S now fully unveiled we thought it was a good time to compare it with the iPhone 4.

A lot of users are complaining that the device isn't a significant improvement on the iPhone 4 they expected, so we thought we'd do a study of the similarities and differences between the two smartphones.

iPhone 4S (3.5 inch Retina Display 960*640p) v iPhone 4 (3.5 inch Retina Display 960*640p)

The iPhone 4S has the exact same screen and resolution as the iPhone 4, which  is slightly disappointing. However, the display is still one of the best around and while we would have liked a bigger screen it'll just have to do.

• Processor

iPhone 4S (Apple A5 Processor) v iPhone 4 (Apple A4 Processor)

One of the biggest hardware improvements comes in the new A5 processor that features on the iPhone 4S. The new A5 dual-core processor , which debuted on the iPad 2, is up to 7 times faster than the one found in the iPhone 4. 

Even though quad-core mobile processors are now in the works, you'd have to say that the iPhone 4S CPU is a significant improvement over its predecessor.

• Camera
  

iPhone 4S (8 mega-pixel camera) v iPhone 4 (5 mega-pixel camera)

Even though the iPhone 4 camera took fantastic pictures it was often criticized for its low mega-pixel value compared to other premium smartphones, as well as the lack of 1080p video recording. The iPhone 4S fixes these criticisms with the addition of an 8 mega-pixel camera which can record 1080p.

The iPhone 4S has exactly the same dimensions as the iPhone 4 (115.2 x 58.66 x 9.3 mm), but due to the extra hardware the weight has increased from 137 grams to 140 grams.

• Onboard Memory 

iPhone 4S (16,32 and 64GB) iPhone 4 (16GB and 32GB)

The iPhone 4S introduces a version with larger on-board memory than was available on the iPhone 4. The new 64GB is a good improvement that could also be needed by some people due to the new HD content, better camera with 1080p video recording and the increasing size of applications.

• Software

iPhone 4S (iOS 5) v iPhone 4 (iOS 5)

The latest version of Apple's operating system (iOS 5) comes pre-loaded on the iPhone 4S, but you can update your iPhone 4 to iOS 5 as well. Therefore , on first sight it might seem like there hasn't been any software improvements , but Siri is exclusive to the iPhone 4S.

• Siri 

Verdict

The hardware improvements bring the iPhone 4S right up to date with the rest of the smartphone world , while a bigger screen would have been welcomed it is still a great display. But its Siri that really sets the iPhone 4S apart.

We think Apple have again brought another innovate device to the market that will go on to achieve record sales.

You can buy the iPhone 4S from Three by clicking here.