For the past few years, AMD has worked on a new generation of external GPU technology that would use Thunderbolt 3 and offer a better experience. This push got a major boost when Apple announced back in June that the MacBook Pro line would support this functionality. eGPU support is still being built into macOS High Sierra, but it's now in a sufficient state for testing.
9to5 Mac(Opens in a new window) took a Mantiz Venus MZ-02 chassis for a spin to find out what kind of performance upgrade Mac users might expect from adopting a high-end GPU. The results are early -- hardware isn't properly identified, and the author may have made a mistake in his hardware configurations, given that he tested Rocket League with vertical sync enabled. While that's a reasonable option when it comes to how you personally prefer to handle V-sync, it permanently caps performance of any solution at the maximum refresh rate of the monitor. If your GPU can push 500fps and you lock your frame rate to 60Hz, 60fps is all you're going to get.But, with that caveat in place, we can at least say the RX Vega 64 retains enough of its raw performance to smash through what the MacBook Pro 13-inch is capable of delivering. Unigine Heaven isn't a great test these days -- it's old and synthetic -- but it does show a MacBook Pro 13-inch barely breaking 10fps on its own compared with a smooth 65fps for the Vega 64.
Again, early driver support and imperfect hardware detection makes it clear that it's still early days to be running out to bet on eGPU performance in Apple systems, but the long-term trend is positive. The chassis in question is expensive, at $400, but includes a power supply, can charge the MacBook Pro while gaming, and has SSD mounting brackets, USB 3.0 and gigabit Ethernet support, and a 550W power supply.
Will eGPUs Finally Catch On?
The idea of an external graphics adapter is nothing new, but there are some additions to the concept that I think could lead to wider (if still niche) uptake in the laptop market. First, we know PCI Express 4.0 is coming, and while we don't expect to see hardware supporting that standard until 2018 or 2019 at the earliest, doubling the bandwidth on PCI Express 3.0 will make it cheaper to deliver an external interface that can handle GPU rendering with no performance loss. An x2 PCIe 4.0 connection will have the bandwidth of today's top-end Thunderbolt solution, while an x4 PCIe 4.0 will be equivalent to an x8 PCIe 3.0 or an x16 PCIe 2.0 slot. Since single-GPU bandwidth requirements increase only modestly over time, this should be enough bandwidth for the foreseeable future.
Second, chassis like the one 9to5 tested aren't just for GPUs. The ability to mount an additional storage solution, gigabit Ethernet, USB 3.0, and system charging make this chassis a plausible port multiplier. It could enable users to extend the life of laptops they've previously purchased. If Thunderbolt starts showing up in less expensive systems, this benefit only increases -- instead of spending $1,500 on a heavy gaming laptop, users can buy a smaller system for $500 for travel, hook it up to a $400 eGPU chassis at home, and then plug in a $500 GPU with performance superior to any laptop GPU you can buy. The initial investment is high, but once made, the chassis can be upgraded repeatedly over time.
I'm not convinced eGPUs are automatically the future of laptops, but I can see a plausible way they could become more popular. We'll have to see how many companies are eager to follow Apple's lead once support is firmed up and plugged into the shipping version of macOS.
