Performance: General Usage & Battery Life

The Surface Book is a pretty powerful laptop, with all options packing high-end Intel Skylake hardware. The base model features an Intel Core i5-6300U with two cores and four threads clocked at 2.4 GHz with a Turbo Boost up to 3.0 GHz on a single core, or 2.9 GHz on two cores. This chip features an Intel HD 520 GPU at 1000 MHz, and there's 3 MB of L3 cache. All Core i5 models come with 8 GB of RAM, and either 128 GB or 256 GB of storage.

If you want a faster processor, Microsoft will sell you one with an Intel Core i7-6600U, which features two cores, four threads clocked at 2.6 GHz with a Turbo Boost up to 3.4 GHz (single core) or 3.2 GHz (dual core). There's 4 MB of L3 cache in this model, and a HD 520 GPU at 1050 MHz. Both the Core i7 and Core i5 CPUs have a rated TDP of 15W, are built on a 14nm FinFET process.

All Core i7 models also come with a discrete Nvidia GPU located in the keyboard base. This means that when the tablet is attached to the keyboard, and you're running a graphics-intensive app, the Nvidia GPU will take over the HD 520 GPU in the Skylake CPU. In all other cases, the integrated graphics are used.

While neither Microsoft nor Nvidia have specifically stated what GPU is inside the Surface Book, it's pretty clear from inspection that it's a variant of the Nvidia GeForce 940M. The GPU packs 384 shader cores, 32 TMUs, 16 ROPs, and clock speeds of 954 MHz with a boost up to 993 MHz. It's paired with 1 GB of dedicated GDDR5 frame buffer.

All in all, there are six models of the Surface Book, which are as follows:

  • Core i5-6300U - 8 GB RAM - 128 GB SSD - $1499
  • Core i5-6300U - 8 GB RAM - 256 GB SSD - $1699
  • Core i5-6300U - GeForce 940M - 8 GB RAM - 256 GB SSD - $1899
  • Core i7-6600U - GeForce 940M - 8 GB RAM - 256 GB SSD - $2099
  • Core i7-6600U - GeForce 940M - 16 GB RAM - 512 GB SSD - $2699 - (reviewed here)
  • Core i7-6600U - GeForce 940M - 16 GB RAM - 1 TB SSD - $3199

I'll start with some positive experiences of using the Core i7 model with 16 GB of RAM and the integrated Nvidia GPU. There's no doubting that this is a fast device, whether you use it in laptop or tablet mode. Compared to other tablets, the Surface Book really doesn't have a match at this size class, and simply crushes basic tasks like web browsing, video watching, and document editing.

Compared to my daily driver, a Dell XPS 13 powered by an Intel Core i5-5200U, in basic tasks the Surface Book doesn't feel considerably faster, although the XPS does have the advantage of packing a lower display resolution (1080p vs 3000 x 2000). If you're just planning on web browsing and light productivity tasks, any Skylake Core i5 laptop will suffice, and that includes the lower-spec models of the Surface Book.

The real advantage to having a Surface Book loaded up with a Core i7 CPU and dedicated GPU is the performance it provides in more intensive workloads. Editing photos in Lightroom was noticeably faster on the Surface Book than the XPS 13, as was editing photos in Photoshop. The Nvidia GPU doesn't make a huge difference in this sort of app, but the faster CPU and SSD certainly does.

Microsoft claims the Book is suitable for use in Adobe Premiere Pro as well as in AutoCAD. It's in these two applications, among others, that the Nvidia GPU provides an advantage over integrated graphics. I personally tested Premiere on the Surface Book, which I use for editing videos on a workstation, and the extra performance of the 940M gives a decent performance bump when applying GPU-accelerated effects to your timeline.

On the flip side, the Surface Book is not equivalent to a good desktop PC with even a modest Intel CPU and dedicated GPU. My personal rig is equipped with a modest Intel Core i5-3570K CPU, and for video encoding it understandably crushes the Surface Book. The Surface Book is capable of editing 1080p videos on the go, but you can basically forget 4K editing with the performance it provides.

In other words, the Surface Book is a great device to complement a workstation when you're away from your desk, but it's not meant to replace it.

In intensive workloads, particularly in Premiere Pro, Photoshop and in games, the Surface Book is not quiet. The fans in the tablet spin up under moderate load, and when the CPU really needs to kick into gear, the high-pitched fan tone can become obnoxious. It's audible over audio at a reasonable volume, and in general the laptop is louder (and runs hotter) than my XPS 13.

While I didn't have issues detaching the display, and I didn't experience screen flickering or general instability, I did have some issues getting applications to use the dedicated Nvidia GPU. 3DMark, for example, refused to use the 940M unless I specifically set the "preferred graphics processor" to the Nvidia GPU; setting only 3DMark to prefer the Nvidia GPU didn't work, and automatic selection didn't work either.

Considering automatic GPU selection didn't work for 3DMark (and some other apps), it's hard to know whether when you fire up Creative Cloud apps that the Nvidia GPU is being selected as it should be. You can check this within the app, but when I was using the Surface Book, I was never confident that the software would appropriately choose which GPU to use. I haven't had the same problem on laptops with both integrated and dedicated GPUs - automatic selection has worked well in the past - but on the Surface, users might need to manually select the Nvidia GPU to get the best performance.

The Surface Book has a combined 70 Wh battery, which is above average for this class of laptop. The battery is split between an 18 Wh unit in the tablet, and a 52 Wh unit in the base. Naturally, the tablet's battery life is not great and you'll only manage a couple of hours of web browsing before needing to plug it in to the base.

However, the battery life from the laptop as a whole is excellent. When I used the Surface Book as my workstation for a couple of days, I could pretty much go the entire day (8-10 hours) of moderate to intensive use without needing to charge the unit. I've heard reports that the Core i7 unit doesn't deliver as good battery life as the Core i5 models, but I was still very impressed with what it delivered.

Unfortunately, the Surface Book is still plagued with an issue where the system might not enter a sleep state properly when the lid is shut. This doesn't sound like a significant issue, but there were times when I'd put down the Surface Book overnight without plugging it in, only to discover it was dead the next morning. This isn't something I've experienced with similar laptops, and considering I can occasionally hear the fan with the lid shut, it's clear the Book doesn't always sleep when it should.