We're not going to get super technical here -- if you want to know more about the underlying problems when pairing strong GPUs with weak CPUs, you can read every technical analysis of Sony's PS4 Pro ever written. Instead of geeking out on the CPU's role in gaming, let's just remind ourselves of the machines that Apple has made over the past five years, in rough order of processing power:
- MacBook Air
- Mac mini
- MacBook Pro
- Mac Pro
Which of these Macs, with an added GPU, is "VR-ready"? It depends who you ask. HTC and Oculus began with the same required specs for their respective headsets: Your setup had to involve a CPU equivalent to an Intel i5-4590, a similar GPU to a NVIDIA GTX 970 and at least 8GB of RAM. While HTC has mostly held fast on that specification, Oculus has lowered the baseline significantly. It now suggests the minimum specs required are an Intel i3-6100 and a NVIDIA GTX 1050 Ti. (That's thanks largely to custom software on Oculus' part, and the "recommended" CPU remains the i5-4590.)
Taking the i3-6100 and i5-4590 as our baselines for required CPU performance -- and ignoring port selection for now -- it's immediately apparent that the MacBook, MacBook Air and Mac mini do not meet the minimum required specifications for VR, no matter what GPU you add.
Pretty much every MacBook Pro with a quad-core processor would breeze through the CPU requirement tests: That includes the 15-inch Touch Bar model but also runs back to the high-end 15-inch models from 2013. As for the 13-inch and dual-core 15-inch models, that's up for debate: An i7 might meet Oculus' base spec but would be nowhere near HTC's. We don't yet have full details of the chips inside Apple's new Kaby Lake-powered MacBook Pros, but there's a strong chance the small bump in power will bring even the i5 13-inch Touch Bar model up to Oculus' spec.
Anyone with a trash can Mac Pro, unsurprisingly, has enough theoretical CPU power to handle a VR headset with ease. As does every Retina iMac ever made. But here we get to the other problems: I/O, and speed.
Apple briefly showed a Thunderbolt 3 GPU enclosure containing an AMD RX 580 (a more-than-VR-ready GPU) yesterday onstage. Thunderbolt 3 is a fairly new connector, so that rules out all but yesterday's new iMacs and more-recent MacBooks and MacBook Pros from supporting the dock. Of course, there are Thunderbolt 2 enclosures out there, but even with the increased throughput of Thunderbolt 3, there's a big hit to raw power when using a GPU dock. Factor in the fact that you'd also be relying on the dock's USB ports for data transfer to the VR headset and Thunderbolt 2 docks just don't seem practical in this use case.
So where does this leave us? Apple has clearly put the pieces in place to encourage VR, and gaming in general, in a bigger way on macOS. Valve is adding SteamVR support to the platform, and popular engines like Unreal Engine 3 and 4, Source, and Unity all run on Macs. The groundwork has been laid, and once we get to the point where there's a bank of gaming-ready hardware in users' hands, chances are we'll see more titles supporting macOS.
That hardware is on its way too. The top-of-the-line 5K iMac (and only that model) is VR-ready out of the box, as is Apple's iMac Pro, due this December. It's also safe to assume the new Mac Pro will support headsets with ease whenever it arrives, and we can't be more than a couple of years away from a VR-ready 15-inch MacBook. There are several reasonably sized Windows laptops that pull off the feat already, albeit relying on some very noisy fans to do so, and NVIDIA's new Max-Q tech will make these machines less noisy and power hungry in the months and years to come.
Despite these advances, those wanting a 12-inch or 13-inch Apple laptop with strong VR support are going to be waiting for quite some time. Maybe 360-degree video and other limited-use applications for VR will run, but for the most part the MacBook's CPU prevents it from handling VR experiences well. That doesn't mean that external GPUs are pointless to these machines, though, as graphics cards are useful for a lot more than VR and gaming.
Like most ultraportables, the 12-inch MacBook isn't set up for heavy-duty tasks. (Nor, truth be told, are the 13-inch MacBook Pros, despite the designation.) I used to have an i7 MacBook Air as my daily computer, and design work, video editing and photo processing were a chore. But these "Pro" applications like Photoshop, Premiere Pro, Lightroom and InDesign all support hardware acceleration, and a GPU dock will make using them on an ultraportable Mac entirely viable.
Quite why the dock will cost developers $600 when the GPU inside it can be purchased for under $300, I'm not sure. (In Apple's defense, it's branded as a dev kit, and Razer and other companies charge similar prices for their Thunderbolt 3 docks.) Either way, the RX 580 inside is a strong midrange card, and it will dramatically improve performance across a wide range of applications. Of course, CPU and RAM limitations are still a thing outside gaming, but you would be able to edit video on a 12-inch MacBook without things falling apart. Hell, assuming the drivers are up to scratch, you should also be able to play games quite nicely at lower resolutions and frame rates, assuming the CPU demands of the title aren't too large and that it supports macOS in the first place.
Because of the GPU dock announcement, basically overnight I've become extremely interested in buying a new MacBook when High Sierra arrives this fall. I currently have a (VR-ready) Razer Blade for gaming and a 15-inch MacBook Pro from mid-2015 as my everyday computer. When I'm away from a power outlet, though, battery life on the Pro just isn't good enough. I don't tend to do anything particularly heavy when out and about, but Chrome and Slack alone will near-enough zero the Pro's battery in three hours or so.