If you own an iPhone 4 you may be wondering whether an upgrade to the iPhone 5 is in order. Here we analyse the difference between the iPhone 4 and the iPhone 5, and assess whether you should upgrade from iPhone 4 to iPhone 5. If you are an iPhone 4S user, turn to our story: Should I upgrade to iPhone 5 from iPhone 4S?

iPhone 4 vs iPhone 5: performance

The iPhone 5 with its A6 processor is much, much faster and more responsive than the iPhone 4 (and the iPhone 4S, for that matter). Noticeably so. Using the iPhone 5 apps spring open immediately, removing the short lag that occurs when you tap an app on the iPhone 4. Even web pages load more quickly, which surprised us: we assumed that the connection would be the bottle-neck that slows down web browsing, but the iPhone 5 proves that a faster device can help.

Don't just take our word for it, however. In the benchmark tests we carried out in the PC Advisor Test Centre the iPhone 5 performed staggeringly well in comparison to previous Apple smartphones.

In our Geekbench 2 speed test, the iPhone 4 scores a respectable 326 points. The iPhone 4S comfortably beats it with a score of 634, but the iPhone 5 simply blows both devices away, with a world-beating score of 1650. (All these tests were carried out with phones upgraded to iOS 6 - but the results were virtually the same when the iPhone 4 was tested with iOS 5.)

For comparison Samsung's Galaxy S3 is the best non-Apple high-end smartphone, and it scored a similarly rapid score of 1659 (so close it is, in essence, the same score). So if you are on the iPhone 4, you may be tempted to upgrade on speed alone even if you fancy a change to Android. (Our fastest ever phone is the Samsung Galaxy Note II, which averages more than 1900 points.)

This difference was bourne out by our SunSpider web-browsing speed test, in which a lower score is better. The iPhone passed the test in an impressive 3004ms. The iPhone 4S improved on this with a quicker score of 1891, but the iPhone 5 takes the cake with a staggeringly quick test of just 903ms. The Galaxy S3 scored 1447ms - so the iPhone 5 is the quickest phone for web browsing, bar none (although it is important to remember that the speed of the connection will be the critical factor).

Finally, in our Egypt HD gaming benchmark the iPhone 4 scores 4 frames per second. The 4S comfortably tops this with a score of 19fps, but the iPhone 5 blows them both away with a massive 38fps. And this number may even be higher but for the iPhone 5's V Sync limit, which means it is capped by screen refresh rate.

So in general use, for web browsing and for gaming the iPhone 5 is a whole lot faster than the iPhone 4. If you want a faster phone, it's time to upgrade.

iPhone 4 vs iPhone 5: camera

The iPhone 4 has a perfectly decent camera for a smartphone. Two in fact, as its rear-facing 5Mp still camera is supplemented but a front-facing 640x480 video camera. The 'proper' camera can capture up to 1280x720 video.

The iPhone 5, by comparison, has an 8-megapixel iSight camera facing out from the rear, and a front-facing FaceTime HD camera that captures 1.2Mp photos and HD video (720p) at up to 30 frames per second.

With the full, rear-facing cameras we noticed the difference in test shots. We expect you will too.

It unfair to compare the abilities of both cameras to take close up shots, as the iPhone 5 is able to focus in at short distances and the iPhone 4 simply can't. A more realistic challenge is that of taking a decent landscape shot. We took all of the following images at the same time, from the same position. Click the images to see them at full size (and compare the difference in final images).

iPhone 4 image close up

iPhone 4 image taken close up

 iPhone 5 image close up

iPhone 5 image taken close up

iPhone 4 image from distance

iPhone 4 long shot

iPhone 5 image from distance

iPhone 5 long shot

Suffice to say that while both cameras are decent smartphone snappers, the iPhone 5 could easily replace your compact point-and-shoot. Perversley, if you are a hobbyist snapper this is likely to be less of an attraction, as you probably have a dedicated camera. But if you want your phone to also be your primary camera, the iPhone 5 will be a good upgrade.

iPhone 4 vs iPhone 5: display

The iPhone 4 has a 3.5in capacitive IPS touchscreen with a 960x640 resolution. It's a great screen for a smartphone, and at the time it launched the iPhone 4 had the highest resolution ever for a handset.

But the iPhone 5's display is a step above. For one thing it is taller than the iPhone 4, and as a 4in screen. It is also noticably sharper. With a 1136x640-pixel resolution at 326ppi the iPhone 5 crams in the detail. As the iPhone 4 made the iPhone 3GS' display look dated, so does the iPhone 5 reduce its predecessor. Look at both displays and you'll want the iPhone 5, and held in landscape mode it makes for a great way to watch widescreen movies.

iPhone 4 vs iPhone 5: style and build

iPhone 4 and iPhone 5 Even with the larger screen, at first glance the iPhone 5 looks not dissimilar to the iPhone 4. But look again - as well as being taller than the 4, the iPhone 5 is surprisingly thinner and lighter. Noticeably so. The iPhone 4 measures 115x59x9mm and weighs in at 137g, but the is lighter at 112g and measures only 123.8x58.6x7.6mm - its just 7.6mm thick.

Which you prefer will be a matter of personal choice, but if you like thin and light - even with the bigger screen the iPhone 5 is your phone. We suspect, however, that very few people are unhappy with the weight and size of their iPhone 4.

Both phones are, typically, beautifully constructed. Like the iPhone 4 (eventually), the iPhone 5 comes in both white and black.

iPhone 4 vs iPhone 5: software, connectors

Two other things to consider: the iPhone 5 comes with iOS 6 pre-installed. Your iPhone 4 is probably running iOS 5 or iOS 6, and in time you'll be prodded and nagged into to upgrading to iOS 6. We know that some people don't like iOS 6 on older phones, saying it slows them down, drains the battery and pointing to the lack of Google Maps. Our own tests showed that the iPhone 4 is just a tiny bit slower on iOS 6, although at such a level as you really couldn't notice. But for those who are iOS 6-phobic, the fact that you can choose to stay with iOS 5 may be a plus point for the iPhone 4.

On a similar bent, the iPhone 5 uses the new Lightning connector, rather than the traditional iOS 30-pin interface. This is one of the reasons that the iPhone 5 is so much smaller and lighter. It takes up less space both inside and outside your device. It is also reversable - unlike 30-pin iOS cables - and reports that it includes a microchip suggest a level of intelligent design that means the Lightning cable is future-proofed.

But if you have existing docks and speakers that fit to iPhones and iPods, as well as cables from old iDevices, you need to factor in the cost of replacing them if you upgrade to the iPhone 5. You can buy a Lightning adaptor for £25, but if you are used to having a few around the house, it could get expensive.

iPhone 4 vs iPhone 5: conclusion

The iPhone 4 is still one of the better smartphones around, but the iPhone 5 is - of course - much, much better. In fact, with the possible exception of the Samsung Galaxy S3, the iPhone 5 is head and shoulders above every other phone around. But whether you should upgrade comes down to a few key things: are you prepared to pay extra for a much lighter and faster phone with a more detailed screen and an infinitely better camera? And if you are, are you prepared to shell out further for docks or adaptors?