The majority of gamers play on desktops. It's the most cost-effective, modular way of building a system. As such, advice on specifications from VR manufacturers like Oculus (the Rift) and HTC (the Vive) has focused on desktop hardware. Over the last few years, though, the relative cost of portable gaming components has decreased while their performance increased. Gaming laptops are now a realistic option for people who want to play even the most demanding games.
Virtual reality is different, however. Excitement about VR transcends platforms, but if you run a portable rig, whether it's up to the task is a much harder question. I went looking for answers.
"Most modern machines are capable of running VR," Zak Lyons of the human-computer interaction team at Bath University told me. "However not all of them can run it well. If you put a VR headset on and there's latency when moving your head, you're going to get ill pretty quickly. So it really comes down to whether a laptop can offer a good enough latency-free performance to avoid cybersickness."
Narrowing the question only clarifies things a little. Comb VR forum threads and you'll find a wide range of specifications listed as the minimum for comfortable viewing. You'll also find people who claim VR won't work on laptops at all. Mostly, you'll find people in the middle who've jumped through hoops to get it working on their hardware with varying degrees of success. Getting a definitive answer is difficult.
According to Sam Watts, producer of upcoming VR game Radial-G: Racing Revolved, there may be an element of self-deception involved. "Everyone wanted to believe that portable VR was a viable option," he opined. "So there's a number who insist their experience of VR on laptops is good enough, leading to many threads discussing hacks and workarounds."
This was true until the end of last year, when suddenly nothing seemed to work at all. Both Watts and Lyons believe this was a deliberate choice on the part of Oculus. "Too many people reported issues and poor performance, so Oculus just stopped supporting it," Lyons said. Watts was more forthright. "[Oculus SDK] Runtime 0.8 stops content from launching if you attempt to run on a laptop or PC without a graphics card meeting the baseline requirements," he told me.
Although it sounds drastic, it's a decision rooted in commercial reality. "If someone's first experience of VR performs badly or makes them ill they are likely to dismiss it entirely," Watts explained. "This was a necessity to ensure only those with the required components can run VR, to avoid poisoning the well with poorly performing hardware."
So what are the official baseline requirements for a laptop? Nvidia says you will need a GTX 980. Since they use the same numbers for their desktop and mobile chips, just adding an 'M', you might think that refers to a 980M. You'd be wrong. Under the system specs there's a pale disclaimer saying that the 970M and 980M aren't good enough. What they're talking about is the 980 'notebook', a distinct card with the same power and model number as a desktop 980 but which fits in a laptop.
Having almost identical model numbers for three different chips, one of which is for desktops, is a nightmare. Yet confusing nomenclature is just the beginning. Even now, you'll find people claiming that Nvidia is wrong and that VR does work with high-end mobile graphics cards. This bewildering variety of user experience stems from the engineering fudges needed to get top performance on a portable machine.
"The primary purpose of a laptop is portability," explained Byron Atkinson-Jones, the mind behind sci-fi VR title Caretaker Sacrifice. "As such most of them are marketed around extended battery life and price. That means they have to employ hardware tricks or use cheaper components to make both of those points a reality. Often those tricks and components are incompatible with VR."
For instance, as motion sickness became more of an obvious issue, developers of VR hardware increased refresh rates to stave it off. "When the Oculus Rift DK2 released, the refresh rate of the screen went from 60Hz to 75Hz," Watts said. "The final, commercial versions of Oculus and Vive are already pushing higher resolutions and 90Hz refresh rates. Yet many laptop graphics chipsets aren't capable of operating beyond the native 60Hz of the laptop screens."
Another example is the speed of USB and HDMI ports. "All HDMI is not equal," according to Atkinson-Jones. "You need to be sure that the HDMI port can output at high speed which not a lot of laptops can achieve. And if your laptop’s integrated USB can’t handle the requirements of VR then it doesn’t matter if your GPU can. It’s still not going to happen."
While these issues shouldn't be a problem for most modern hardware, there are other devils to watch out for. The biggest is Nvidia Optimus, technology which decides whether or not to route an application through the dedicated GPU. In most cases this can be a huge boon to battery life. But it has the potential to wreak havoc if the user has a VR headset connected.
"The problem is that even if the dedicated card generates an image, the integrated card is what outputs that image to a monitor," Lyons told me. "With VR, that monitor is your headset. Unfortunately integrated cards just aren't powerful enough to output images to a VR headset without latency. There are workarounds to make VR work on a laptop with Optimus, but since the HDMI port is connected to the integrated card there is no way to bypass it. "
So, does that mean laptops with high-end mobile graphics cards that don't have Optimus are capable of running a VR headset? Maddeningly, the answer is "maybe". Some sources I spoke to reported success with this setup, providing that the CPU and other components in the system were up to the job. Watts, however, had doubts as to whether they'd be up to running games with the final commercial version.
He took me through some calculations to explain the issue. Currently, gaming benchmarks presume a game will be running at 60 frames per second on a single, 1080p display. Oculus, however, has two displays, one for each eye. And their native resolution is 2160x1200 pixels. To achieve the same level of smoothness and avoid motion sickness, the Rift demands at least three times the graphical grunt of a laptop screen. More if there's any significant physics or post-processing effects in the game.
Stacking multiple GPUs is no answer either. "SLI isn't really supported in VR," Watts admitted. "When you're dealing with 9ms per frame at 90Hz, it leaves very little wiggle room. At that rate, if frames aren't perfectly in-sync across both eyes then the experience will cause discomfort." Also, it seems that whether SLI works with a given VR application is partly at the whim of the developer, so support is inconsistent.
Nvidia's answer to all of this is the desktop grade 'notebook' 980 that it recommends. Indeed the existence of this chip feels like a direct response to a demand for portable machines capable of running VR. But that card, which Watts described as "mental", comes with problems of its own. It is, in most respects, a direct equivalent to the desktop version. While that includes desirable things like overclocking potential and no Optimus, it also includes colossal amounts of heat and power drain.
Asus have a startling answer to this in the form of the ROG GX700, which comes with a bulbous water cooling dock. While they claim this provides quieter operations and big performance gains, it's not strictly necessary. MSI, Clevo and other manufacturers offer a range of air-cooled laptops sporting the 980. Most are not yet available in the UK but some of the Clevo models are available via resellers such as mySN. They offer the MySN U716 and U726 models with an option for the 980, and claim they are VR ready.
I wrote this article on one of those machines, with FurMark thrashing the GPU in the background. The stress test results appear to confirm that the hardware is up to the job. My knees confirm that they can, just about, still justifiably claim to be laptops. They're bigger and heavier than existing 17" gaming laptops. Extended use also sees them getting uncomfortably hot, and the battery will barely provide an hour of gaming without a boost. But while you wouldn't want one on your thighs for hours without asbestos trousers, they're still a lot easier to carry around than any desktop PC.
Even if your budget or your trousers aren't up to such monstrous hardware, there's still hope for laptop users. "There are lower spec VR headsets such as Razer's OSVR," Watts suggested. "It's only 1080p, offering 60Hz and 120Hz operation, similar to the Sony PSVR. So it's more suitable for a wider range of hardware, but doesn't offer the best of current VR technologies available." Whatever you're packing, it seems that the reality of VR on a laptop needn't be virtual for much longer.