Exploring Thunderbolt 3 eGFX Performance, Feat. PowerColor's Gaming Station & Radeon RX Vega 56 Nano

Closing Thoughts

It's been a while since we've had a real chance to dig into the performance of any Thunderbolt 3 peripherals, so PowerColor Gaming Station eGFX enclosure gave us a good chance to look at their latest box while doing some extra testing, especially on the bandwidth side of matters. We're a couple of years into eGFX enclosures now, so admittedly PowerColor's enclosure hasn't shown us anything terribly unexpected, but it's been a fun experience trying to nail down aspects such as PCIe bus utilization and how much the narrower TB3 bus can impact graphics cards.

As far as PowerColor's Gaming Station enclosure goes, the industrial design is passable. With its all-metal chassis it is sturdy and doesn't feel cheap, and the box is designed in such a way that even with just a single fan there's plenty of ventilation for any installed video card. The 550W PSU is internal and it supports very large and power-hungry GPUs. We encountered no firmware issues when testing across a number of different systems.

With that said, there are a few aspects that could do with some improvements. For example, the configuration of the USB 3.0 hubs in the board could lead to bandwidth bottlenecks in certain usage scenarios. Since the Alpine Ridge controller can act as a USB 3.1 host, PowerColor could have gone in for a USB 3.1 Gen 2 hub. Finally, the enclosure could add a mount option for a 2.5" drive internally, given that the SATA port has been brought out of the board. All said, the Gaming Station performs well and has features that are similar to the enclosures in the same price range.

Meanwhile turning our eyes towards the Radeon RX Vega 56 Nano that PowerColor also sent along, we had the chance to test it in the same system as the NVIDIA GTX 1070 Founders Edition. In general, the Vega 56 Nano edges that out slightly in terms of frame rates across most of the games. However, this comes at the cost of power consumption (as our experience with the Shuttle's 500W PSU showed). On the whole, this is a card that consumers will appreciate for its compact nature, especially for those already entrenched in AMD's ecosystem.

Putting the two together, the big question is whether the limited bandwidth of TB3 and the eGFX chassis bottlenecks the Vega 56 Nano's performance, and the answer to that is generally no. Though not without some caveats.

The biggest limitation typically isn't the TB3 bus in these scenarios, but rather CPU bottlenecking by the low-power CPUs used in laptops and mini-PCs. Unless a game is heavily GPU-limited from the start, then it's a lot easier to become CPU-limited in these scenarios by pairing a fast GPU with a thermally-limited CPU. Which means adding an eGFX chassis can add a lot of performance to gaming in these devices, but only up to levels that the CPU allows. In practice this means that high resolutions with high quality settings tend to near parity with full desktops, while lower resolutions that are chasing high framerates will struggle. This means it's possible to buy a video card that's too powerful for some of these mobile and miniature devices, however we contend it's also a really good excuse to justify gaming on a nice 1440p or 4K monitor instead.

Looking at the TB3 bandwidth situation more broadly, PowerColor's Gaming Station was able to keep up with our USB transfer test even when running 3DMark. And while the total amount of bus traffic is going to vary from game to game, it's a solid indicator that the TB3 link isn't so saturated that it's struggling to keep up with just the GPU workload. With PCIe 4 around the corner I don't think anyone would mind having a matching Thunderbolt 4 to create an even faster external link, but right now TB3 looks to be more often than not sufficient.

Wrapping things up, eGFX solutions have been investigated by users ever since Thunderbolt 2 came into the market. With Thunderbolt 3, Intel has finally delivered official support. The certification program ensures that eGFX enclosures follow strict guidelines (such as not being part of a daisy chain, or, not having more than one GPU slot). This has enabled the ecosystem to deliver a consistent user-experience to consumers. The PowerColor Gaming Station is a certified eGFX enclosure. Along with XConnect-compatible GPUs such as the PowerColor Radeon RX Vega 56 Nano, it enables a relatively portable gaming / GPU workload accelerating solution that can be easily used across multiple systems.