Sony Ericsson has managed to go the whole year using the same processor for all of its Xperia smartphones. The Qualcomm Snapdragon processor, running at 1GHz, is accompanied by an Adreno 205 graphics co-processor and has helped the company shift 22 million Xperia's to date.

But it isn't dual-core, and to many that means it's yesterday's news. Despite not being dual-core, when tested against the supposedly more powerful rivals, it has fared exceptionally well.

Most dual-core smartphones (tablets possibly excepted) aren't pushed hard enough for the extra power to be required in most cases, any more than most people need 20-megapixel cameras to upload photos to Facebook.

In fact, for most of the time you'll be hoping the processor can idle along, in order to help the battery last more than a few hours.

The original arc didn't just come with an impressive processor. Sony Ericsson started the year by launching a device that introduced the f/2.4 Sony Exmor R camera sensor (with the same technology now finding its way into the iPhone 4S), a bright screen with Mobile BRAVIA Engine software and an HDMI output. It was also exceptionally thin and had a design that didn't just look like any other smartphone.

The arc S is the same phone, with the only change being the processor is now clocked at 1.4GHz. The battery is the same, at 1,500mAh, the camera remains unchanged at 8.1-megapixels, with 720p video recording, and the screen is the same 4.2-inch LCD that displays 480x854 pixels; higher than most other Android handsets.

Hardware wise, the processor is the same MSM8255 chip from the arc, but rated to run at speeds of up to 1.5GHz. Anyone with a bit of technical know-how can root the original (and any other 2011 Xperia smartphone) and clock it at speeds of up to 1.9GHz, but kiss goodbye to the warranty.

The arc S is a fully approved hardware mod, and it also means you don't need to go hacking the phone. What's more, you can now get the phone in white. It gives the new model some exclusivity, as well as letting people know you've got the faster model.

With such a nice screen, you'll want to use it to play games, movies and view pictures. It doubles up as an excellent media player, especially if you get a HDMI cable to connect to your HD television.

The arc S also gets the latest firmware (it's coming to the arc too, so be patient) to enable the USB On-the-Go mode, which means you can connect flash drives, keyboards, mice and game controllers via the forthcoming LiveDock accessory, or a third-party USB adapter.

In the future, besides watching films or viewing your camera photos on a big screen, you'll also be able to play games designed for the Xperia PLAY. You begin to wonder if there's anything the phone can't do.

Other new additions to the new software (which also takes the phone up to Android 2.3.4) includes a more customisable version of Facebook inside Xperia, letting you choose which applications will pull data from Facebook, and a new way to share things by – for example – dragging apps to the top of the screen and sharing it via Facebook.

The home screen has been given a few tweaks too. Previously you could put apps and shortcuts in a folder that showed a single icon. Now, you get miniature icons showing the shortcuts contained inside, iPhone-style.

When using the camera, there's now a new feature called 3D sweep panorama. Invented by Sony, it uses a single image sensor to capture a 3D image when you turn the handset to capture a panoramic photograph (the phone stitches the images together automatically). It takes practice to pan the phone smoothly enough to capture a 2D image, let alone 3D, and unless you've got a 3D television the feature will be useless. The phone can only display 3D images when output to a television.

Again, these features are all coming to the arc any day now, so there's no reason to upgrade from an arc unless you're desperate for the extra speed. But is the phone actually that much faster?

On paper, 1.4GHz is a fair bit quicker than 1GHz. Sony Ericsson claims the camera will fire up around 25% quicker than the arc. In our side-by-side text, it seemed about the same. In fact, side-by-side it seemed like the two phones were identical for every comparison.

Does this mean something was wrong with the arc S? No, it just shows the processor was already more than adequate in the first place.

To actually determine what advantages the phone could bring to enhance things like games (especially 3D rendering), I had to do some benchmark tests. Two popular tools are Quadrant, for raw processing power, and Neocore, which tests the GPU. Quadrant finally revealed a speed increase, if only a moderate one at 1,593 over 1,385, but Neocore came back with a real shock to the system; it arc S achieved a lower frame rate than the arc (58.5fps vs 59.3fps).

Xperia arc (left) - Xperia arc S (right) Xperia arc S (left) - Xperia arc (right)

There had to have been a bug there, or some rational explanation that I can't figure out. Please do tell me if you know why!

If you already own an arc, you were probably hoping to learn about all the reasons to upgrade. Unlike the iPhone 4S over the 4, you really cannot seriously consider an upgrade to this unless you really fancy it in white. If you really want to boost the performance, go ahead and overclock your original phone instead.

In 2012, Sony Ericsson will its all-new portfolio of phones and dual-core will become the new standard. Hopefully, it will also bring more RAM and app storage space. Until then, the arc S takes an already fantastic phone and improves upon it, if only slightly.

If you were in the market to buy an arc, the S is the one to go for if you can, but don't feel you're missing out by searching out a better deal on the older model instead. Either way, you'll end up owning a great all-rounder that can stand up against the faster rivals.