Now that the mighty Surface Book has joined Microsoft's ranks, deciding which Surface to buy has become that little bit trickier. Here, we'll run through the key differences between the Surface Pro 4 and the Surface Book, and explain why you'd want to choose one over the other.
While the Surface Pro 4 was advertised as the tablet that could replace your laptop, the Surface Book goes one step better – this is the device that can potentially replace both your laptop, your tablet and potentially your desktop PC, too.
The Surface Book looks and feels like a lovely laptop should – it just so happens that the screen detaches and turns into a huge 13.5in tablet that weighs only 728g. As a tablet, it has all the benefits of the Surface Pro 4: it works beautifully with the supplied Surface Pen, and it's light enough to be genuinely usable as a stylus-powered notepad or sketchbook. The downside is that only one-third of the battery is in the tablet, and the other two-thirds are hidden beneath the keyboard. As a laptop, it only loses out due to its weight: at 1.51kg, it's a considerable 380g heavier than the Surface Pro 4 with Type cover attached.
The Surface Pro 4, on the other hand, is a tablet which just so happens to do a passable impression of a laptop – or at least it does if you also buy the $199 Type Cover. This clips magentically to the Surface Pro 4 and adds a very usable keyboard and touchpad in a slim 380g package. The downside? The keyboard is relatively thin, so is bouncy and flexible compared to the Surface Book. Also, as the Surface Pro 4 relies on a kickstand to stop the tablet from toppling backwards in laptop mode, it's not great when sat on a lap – as all the weight is in the 786g tablet, it's very keen on toppling backwards.
The Surface Pro 4 is a brilliant tablet, and a reasonable laptop, but – even if it won't appeal to everyone – the Surface Book is the device which gets closest to offering the best of both worlds.
Winner: Surface Book
You have to hand it to Microsoft: the Surface family has some of the most lovely-looking displays of any device out there. Both the Surface Pro 4 and the Surface Book are at the top of their game, but there are some subtle differences to be found.
While the Surface Book has a 13.5in 3,000 x 2,000 display, the Surface Pro 4 has a 12.3in 2,736 x 1,824 pixel display. This might initially look like an obvious win for the Surface Book, but a quick bit of maths calculates that both displays actually have an identical pixel density of 267ppi.
Colour accuracy, brightness and contrast levels are where the Surface Book outdoes the Surface Pro 4, however. The Book is brighter (435cd/m2 vs 400cd/m2), more accurate (it has an average DeltaE of 1.01 vs 1.61) and contrast is significantly better (1,736:1 vs 1,316:1). The only area where the Surface Pro 4 wins out is in the range of colours it reproduces: it covers 97.5 percent of the sRGB gamut to the Book's 96.5 percent.
Would you notice the difference between the two at a glance? Probably not. But the Surface Book's slight improvements and larger screen give it a marginal edge over its stablemate.
Winner: Surface Book
Performance and battery life
On the face of it, both devices have very similar processors and hardware. One key difference is that the Surface Pro 4's entry-level model uses one of Intel's power-efficient Core m3 processors, whereas the Surface Book only comes in Core i5 and Core i7 flavours.
Why does Microsoft make a Core m3 version of the Surface Pro 4? Simply because it provides longer battery life than the Core i5 and Core i7 models, albeit with a trade-off in raw performance. If you want a truly mobile tablet, and don't mind sacrificing a little power, then it's a great option to have.
In every other regard, the pair of Surfaces are very similar. The Core i5 and Core i7 processors which Microsoft employs for both models are virtually identical; they both use DDR4 RAM; and both have super-fast NVMe SSDs. The main difference is that the Surface Book also squeezes in a GeForce GT 940M GPU into the base which gives it a massive boost in graphics performance – if that matters to you, it's a big, big plus.
Battery life also puts a clear distinction between the two. The Surface Pro 4 has a single 42Wh battery, whereas the Surface Book has an 18Wh battery in its tablet section, and a further 51Wh battery in the keyboard. Of course, this means that the Surface Book only lasts a couple of hours in tablet mode, but it's between 20% and 40% longer lasting than the Surface Pro 4 with the keyboard attached.
Winner: Surface Book
This is where the biggest gulf opens between the two devices – whichever way you cut it, the Surface Book is much, much more expensive than the Surface Pro 4. For instance, you can pick up the cheapest Surface Pro 4 with the $199 Type Cover for $1,349, whereas the cheapest Surface Book costs a whopping $2,299. For that money, you can even get a Surface Pro 4 with twice the storage space and still have more than $200 spare.
However, if you have your heart set on one of the GPU-equipped Surface Book models, then you better hope to find a large wodge of cash down the back of the sofa: the cheapest GPU-equipped Surface Book costs £1,599. There's no getting around it, the Surface Book is seriously, extravagantly expensive.
All told, the Surface Pro 4 is a considerably less wallet-lightening purchase than the Surface Book. And yet it's still ruddy lovely.
Winner: Surface Pro 4
You'll have noticed that the Surface Book has (narrowly) won all the categories in this head-to-head barring value for money – but that's probably the most crucial tipping point for most people. Personally, I have a soft spot for both devices, but given my needs, it doesn't matter that the Surface Book is faster, longer-lasting or better in laptop mode. The Surface Pro 4 is simply a much better fit.
The Surface Pro 4 isn't great on a lap, but it's workable for those times when I want to quickly tap out a news story or an email on the train to work. And as it's half the thickness and substantially lighter, it's a darn sight more portable; for someone who often commutes to work by bike, that makes a big, big difference.
The Surface Book is by far the better laptop – it's leaps and bounds better – and the optional GPU completely smashes past the Surface Pro 4 for gaming and GPU-acceleration duties. But then again, if gaming performance was absolutely key to your buying decision you probably wouldn't be buying either of these devices. A $2,299 laptop equipped with a mid– to low-end GeForce GT 940M GPU would be comprehensively flattened by a similarly-priced mobile workstation or gaming laptop.
The final decision is simple. If you primarily want a luxurious, powerful laptop, then the Surface Book is the right device for you. If you want a do-it-all tablet that can pull off a decent laptop impression, then the Surface Pro 4 is an elegant, and much more affordable option. Whichever you buy, you're onto a winner.
Winner: It's a draw