For the past week, I’ve been working on a review of the iPad Pro. For better or worse it has been a very quick week and I’ve been working on the review right up to the embargo time. Rather than rushing out our review of Apple's first large-format tablet in an incomplete state, I'm going to hold it back so that we can get it right and produce the kind of high-quality article that we're known for.

Instead for today's embargo I want to take a more personal look at one segment of the iPad Pro's new features as a preview of things to come. The iPad Pro is a tablet of several firsts for Apple - their first large-format tablet, their first tablet with Apple's A9X SoC, and their first tablet clearly geared towards productivity as opposed to content consumption - and as a result one area that’s worth discussing in depth is whether or not the iPad Pro is useful to people that might not have wanted or needed an iPad before. With the iPad Air 2, for example, I felt quite strongly that while in some ways the larger display than a phablet or a mini tablet was useful, it was difficult for me to justify the cost of the tablet due to the lack of some productivity-focused tools.

Probably the simplest example of productivity use for someone like me is taking notes in class. While you can use a Bluetooth keyboard or a capacitive stylus with tablets like the iPad Air 2, they’re both notably flawed. Typing on a Bluetooth keyboard is often difficult when the keyboard on most of these tablets is usually too cramped/small, so relative to a normal laptop the iPad Air 2 would be at a disadvantage. Using a traditional passive capacitive stylus is also not particularly helpful because the tip is often extremely wide and makes it difficult to write with any precision. There’s also no real palm rejection with passive capacitive styluses, so the experience is pretty frustrating.

At the end of the day, with the iPad Air 2 and most tablets in general I found that trying to take notes with a tablet, whether with a keyboard, stylus, or both was slower than just taking out a sheet of paper and a pencil. Given the amount of coverage on the Apple Pencil and iPad Pro, I wanted to see for myself whether the iPad Pro would be able to replace pencil and paper for notetaking speed. To do this, I took the iPad Pro to class and simply relied on the built-in Notes application to try and see how well I could follow along in lectures and discussions. While some classes are such that words are sufficient to capture what is being said, with math and a lot of engineering classes I’ve found that a traditional QWERTY keyboard is just too slow to keep up at times when equations with Greek symbols and other notation that requires ALT key codes that are basically impossible to remember and quickly type out. The other problem is drawing diagrams, graphs, or anything that is otherwise extremely difficult to recreate solely with a text editor.

As a result, when taking notes on a tablet it's in my experience that it’s necessary to have a good stylus to be able to write out these various symbols, especially when writing quickly. This includes elements like well-tuned palm rejection, low inking latency, good pressure sensitivity, and good pressure to line width mapping. It’s also necessary to have high precision, such that the inking is exactly where the tip contacts the display, which can be difficult especially when using the stylus at an extreme angle. It’s also necessary for the stylus to be comfortable like a good pen or mechanical pencil for it to be something that is familiar and easy to learn rather than something that carries a significant learning curve. Something as simple as the way the tip interfaces with the glass of the display can really make the experience painful. If the tip is excessively sticky, slick, or soft it might be hard for a person to be as accurate and precise with a stylus when compared to more traditional writing instruments.

With this in mind, when I first picked up the Apple Pencil I noticed that the ergonomics and weight of it are within reason and comparable to a traditional pencil or pen. The one issue here that I continue to notice is that the glossy plastic has a tendency to feel a bit gross after a while as oil from the skin and dust can combine to form a sort of grime that tends to feel disconcerting when touched.

Pairing the stylus is accomplished by plugging it into the iPad Pro that the Apple Pencil will be used with. The Pencil seems to need Bluetooth, and turning it off on the tablet renders the stylus nonfunctional until Bluetooth is enabled again. If the stylus is unable to pair with the tablet for a period of time, it seems that re-pairing is necessary by plugging the Apple Pencil into the tablet again but initial setup is relatively painless, although ideally there shouldn’t need to be any re-pairng process.

As the iPad Pro is still relatively new, most applications don’t really support Apple Pencil extensively. As a result, I conducted this test solely using the pre-installed Notes application, which is relatively simple with only support for text input and inking with the Apple Pencil. The drawings that are created with the stylus appear to just be images to the end user, which can be re-arranged and edited at will.

In order to go through a discussion section, it is often the case that rather than another lecture rehashing concepts covered in previous lectures the instructor will give a problem set that is worked through over the course of the discussion, in the hopes that doing problems will help with learning. As it is often logistically difficult for an instructor to print out 30-50 copies of these problem sets, problem sets are often posted online as a PDF. With the iPad Pro, I found that there was no real need to print out these problem sets, as using the multitasking function to keep a PDF and the Notes app open simultaneously is genuinely useful and productive. Of course, this isn’t going to be unique to the iPad Pro or even iOS, but at this screen size this multitasking capability is useful when compared to something closer to a phablet in size.

Of course, these are all just tertiary aspects compared to actually taking notes and solving problems. In this regard, I think the Apple Pencil is surprisingly good. The first thing that I noticed here was that the friction of the tip against the display doesn’t feel like it’s off or wrong in some way. It’s really hard to say exactly what parameters lead to this feeling, but the rigid matte plastic tip has some kinetic friction to help with controlling movement fluently and also low static friction which means that the initial stroke is easier to control than some styluses that I’ve tried with soft, rubbery tips that tend to drag quite a bit.

The actual latency of the stylus is pretty much at the point where I can’t really notice it. I would say that the lagging distance between the tip and inking when moving a sufficiently fast pace is probably less than 5 mm at max, which is enough that I don’t really worry about latency even when I’m writing as quickly as possible to keep up with a fast-paced lecture. The pressure sensitivity is also surprisingly good, as something I’ve noticed with at least a number of stylus implementations is that very light touches are often ignored, and in order to see a proper difference in pressure levels it often seems that it’s necessary to apply significant pressure that is often in excess of what an actual writing utensil would take before damaging paper or something else. Precision is also incredibly good. Out of casual interest, I took a ruler and attempted to slowly draw straight lines in various angles to see if any wobble would occur. Regardless of pen orientation, lines remained straight as long as the tip didn’t vary its distance to the ruler.

The other aspect that I think really helps with proper use of the stylus is actually the sheer size of the display. With paper and pencil, the paper is always at the same height as where the hand rests, so writing is natural and relatively easy. Smaller devices are generally more difficult to accurately use the stylus with as a result, as the hand is usually resting on a desk so the phone is elevated relative to the hand or the writing hand is free-floating. I didn’t really think about this, but this is an ergonomic issue as well that I didn’t have with the iPad Pro, as my hand was usually resting directly on the display rather than being off to the side of the device.

The final aspect of the user experience here is software, and in that regard the Notes app is great for what’s implemented, but the features implemented are relatively few. In some ways this is exactly like paper because there’s no real way to transcribe notes taken with the Apple Pencil to a word processing document. However, I think the iPad Pro is probably the only device I’ve ever tried that comes close to actually achieving the same feel as pencil in paper. Obviously, there’s much more to this tablet than just how the stylus behaves, but so far the Apple Pencil is a seriously impressive stylus. Whether this is comparable or better than competitors like the Surface Pro is something I'm going to hold off on discussing until the full review - that alone can be quite the discussion - but so far I’ve found the iPad Pro to be a great tablet.

The A9X SoC & More To Come

Finally, as everyone is undoubtedly eagerly anticipating our look at the A9X SoC inside the iPad Pro, let’s take a very quick look at what we know about the SoC so far. There’s a bit of a limit to what we can do blindly via just software, but I’m hoping that the eventual A9X die shots will confirm some of our suspicions on A9X’s configuration.

First and foremost, the most unexpected news here is that unlike A8X, A9X is not packing a triple-core CPU. Instead A9X drops back down to just a pair of Twister CPU cores. The twist here is that relative to A8X and A9, Apple has cranked up their CPU clockspeeds. Way, way up. Whereas the iPad Air 2 (A8X) shipped at 1.5GHz and the iPhone 6s (A9) at 1.85GHz, the A9X sees Apple push their clockspeed to 2.26GHz. Not counting the architectural changes, this is 22% higher clocked than the A9 and 51% higher than the A8X.

The fact that Apple dropped back down to 2 CPU cores is unexpected given that we don’t expect Apple to ever go backwards in such a fashion, and while we’ll never know the official reason for everything Apple does, in retrospect I’m starting to think that A8X was an anomaly and Apple didn’t really want a tri-core CPU in the first place. A8X came at a time where Apple was bound by TSMC’s 20nm process and couldn’t drive up their clockspeeds without vastly increasing power consumption, so a third core was a far more power effective option.

By comparison, with the FinFET process Apple is using here – and given the lower volume of A9X I don’t have reason to believe it’s dual-sourced, so it’s either TSMC or Samsung – Apple has been free to increase their clockspeeds substantially. At the same time these FinFET processes are still new and yields won’t be great, so there is a strong incentive to keep die sizes down to keep yields up, and adding a third core would only make that harder. If I had to guess, Apple only wanted two cores to begin with – this makes it easier for developers knowing that they only have two cores to work with – and that it’s A8X that is the anomaly.

Otherwise a highly clocked CPU is far more in-line with Apple’s design philosophy as it means that A9X is capable of amazing single-threaded performance – and keep in mind that we’re talking ARM Cortex-A57-like clockspeeds for a CPU that gets much more work done per cycle – so what we see here makes a lot of sense. Plus with iPad Pro in particular Apple has more battery capacity to sustain the power draw of a higher clocked SoC, and more surface area to dissipate that heat, so the usual concerns about power and cooling aren’t quite as pressing. I do wonder if this will impact multitasking performance much, but given what Twister is capable of, I’m not nearly ready to write off a dual-core Twister implementation clocked this high.

Moving on, as is customary for the X-series SoCs from Apple, A9X features what I believe to be a wider 128-bit LPDDR4 memory bus. The memory bandwidth numbers clearly point to a wider bus, and Apple needs the bandwidth to feed a more powerful GPU.

Which brings us to the last bit of our preview, the GPU. Apple went with a 6 cluster PowerVR Series7 design on A9, and for A9X they have gone with a larger design. Without a die photo it’s basically impossible to determine how many clusters are in use since clockspeed plays such an important role. What we do know is that GPU performance relative to A9 has pretty much doubled, which once again is right in-line with Apple’s usual design goals.

Given what Apple has done with clockspeed on Twister, for the moment I am staking my bet on it being a 10 cluster design with a higher GPU clockspeed than A9 giving us the rest of the performance boost. To be clear here this could also be a 12 cluster design at a similar clockspeed or even an 8 cluster design clocked far higher – we’ll need die shots to confirm – but given all of the options it’s a 10 cluster design that is the best balance between die size and clockspeed, and it would also be the biggest curveball Apple could throw. It should also be noted that PowerVR Series7 certainly supports such a configuration since it’s scalable from 2 to 16 clusters, although in Imagination’s official product catalog they don’t have a name for such a configuration. So for the moment I’m simply calling it a 10 cluster Series7.

Anyhow, we’ll be back later with a full review of the iPad Pro, including the pros and cons of Apple’s first large-format, productivity-oriented tablet, and a full breakdown of the A9X SoC. So until then stay tuned.