Sony announced not one but three new flagship smartphones at IFA 2015 in Berlin, with the leader of the pack going by the name of the Xperia Z5 Premium.

The Sony Xperia Z5 Premium sports some impressive specs, with its highlight being the 5.5-inch 4K display with a whopping 806ppi to make it the sharpest smartphone screen out there.

We have put it up against the Apple iPhone 6 Plus, which also sports a 5.5-inch display, to see how the two devices compare, what the differences are and which of the two smartphones comes out on top when the numbers have been crunched.

Both the Sony Xperia Z5 Premium and the Apple iPhone 6 Plus shine when it comes to design. They both offer a quality build and they both look great, even though they are quite different.

The Sony opts for the traditional OmniBalance design that we have come to expect from the Xperia Z line of devices, offering an aluminium frame in between glass front and rear panels. The edges are flatter than previous Xperia Z devices and the circular signature side power button has been replaced with an elongated side power button that doubles up as a fingerprint sensor.

The Apple iPhone 6 Plus goes for a slightly rounder approach, with curved edges and an aluminium casing. You'll find the power button on the side again, but the fingerprint sensor, known as Touch ID, is found in the home button on the front of the device.

In terms of numbers, the Xperia Z5 Premium measures 154.4 x 75.8 x 7.8mm compared to the iPhone 6 Plus that measures 158.1 x 77.8 x 7.1mm so the Sony is a little fatter but has a smaller footprint overall. The iPhone 6 Plus is a little lighter though, weighing 172g compared to the Z5 Premium's 180g.

The Xperia Z5 Premium comes in black, gold and chrome colourways, with the latter delivering a mirrored finish for those that really want to grab attention. It is also IP65 and IP68 waterproof. The iPhone 6 Plus comes in silver, space grey and gold, but if you drop it in the bath, it will be far from happy.

As we mentioned previously, both the Sony Xperia Z5 Premium and the Apple iPhone 6 Plus have 5.5-inch displays – but they certainly don't have the same resolution.

The Xperia Z5 Premium is the first smartphone to boast a 4K display, meaning a resolution of 3840 x 2160 pixels for a whopping 806ppi, sharper than any other smartphone out there, including the iPhone 6 Plus that settles a 1920 x 1080 for a 401ppi.

Whether the detail provided by the Xperia Z5 Premium is visible to the naked eye is a different story, but it certainly blows the iPhone 6 Plus out of the water here in terms of numbers. Both are IPS displays, but Sony adds some additional technologies to its display, such as X Reality that in the case of this device, will upscale content to 4K resolution.  

Sony made a big play for the camera angle when it launched its Xperia Z1 smartphone back at IFA 2013 and despite all the succeeding Xperia Z devices having the same sensor as the original, things have been stepped up a notch for the Xperia Z5 range.

The Xperia Z5 Premium features a 23-megapixel rear camera with a maximum sensitivity of ISO 12800. Sony has been dabbling with the Sony Alpha section of the business in order to introduce a super fast auto focus system to the Xperia Z5 range though, with the company claiming the rear camera will focus in up to 0.03 seconds. Image stabilisation has also been improved and Sony also claims you'll be able to get a clear image even at 5x zoom. Thanks to the 4K display, users will be able to capture and view 4K content all on the one device. A 5-megapixel snapper is also present on the front of the Xperia Z5 Premium.

The Apple iPhone 6 Plus is a tough cookie to beat when it comes to taking a decent shot, with the Cupertino company's devices known for being perfectly capable. Going by numbers alone however, the Xperia Z5 Premium wins on the megapixel front with the iPhone 6 Plus opting for an 8-megapixel rear snapper and a 1.2-megapixel front camera.

The hardware of these two devices is a little harder to compare as Apple doesn't offer a great deal of detail on the speed of its processors, RAM or even the size of its batteries, but we will give you the run down anyway.

The Sony Xperia Z5 Premium features the Qualcomm Snapdragon 810 processor, supported by 3GB of RAM and 32GB of internal storage. There is also a microSD slot for storage expansion up to 200GB.

The Apple iPhone 6 Plus features the A8 processor and M8 motion coprocessor, with storage options of 16GB, 64GB and 128GB but no microSD support. The RAM is not detailed.

In terms of battery, the Xperia Z5 Premium has a 3430mAh capacity, which Sony claims will last up to two days. Apple doesn't provide details of the iPhone 6 Plus battery in mAh, but while the iPhone 6 Plus lasts longer than its baby brother, two days would be a big stretch. That said, the Sony hasn't been reviewed yet and with that 4K display, two days could be a little far fetched for Xperia Z5 Premium too.

The Sony Xperia Z5 Premium will launch with Android Lollipop, along with Sony's UI over the top. You get a number of bundled apps, such as Sony Walkman, as well as a range of services such as Xperia Lounge. It is also likely to see an update to Android Marshmellow eventually, when that launches later this year.

The Apple iPhone 6 Plus runs on iOS 8, which will soon be upgraded to iOS 9, with Apple holding an event on 9 September, thought to be the launch of the new software.

Ultimately when it comes to software, it will boil down to personal preference. There are benefits to both platforms and it’s likely you’ll already know which you prefer.

The Xperia Z5 Premium comes with the added advantage of PS4 Remote Play, which is a great addition PlayStation owners, while the iPhone 6 Plus is good for those that use other Apple devices with features like Continuity tying them all seamlessly together.

So which device is the winner where the specs are concerned? The Sony Xperia Z5 Premium is smaller than the iPhone 6 Plus, but it is also thicker and heavier. Both have the same size displays but the Sony packs in double the pixels per inch resulting in a sharper, crisper image.

The Xperia Z5 Premium also wins the camera megapixel battle, although it is worth remembering that it isn't just about the megapixels. Both devices are going to be pretty speedy in terms of processing power, but the Xperia Z5 Premium is probably going to pip the iPhone 6 Plus to the post here too, as well as in battery life.

The Sony Xperia Z5 Premium takes the lead in almost all sections but the Apple iPhone 6 Plus is one popular device so the battle is only just beginning. If you're after a device with the highest specs, the Xperia Z5 Premium wins in this case. If you're more interested in design and software, you have a tougher decision on your hands.