Asus' Pricey, Proprietary Mobile RTX 4090 eGPU Arrives, for $1,999

Asus' ROG Flow X13, Z13, and X16 are powerful laptops with some of the top hardware on the market. But they rely on ROG XG Mobile GPUs for high-end gaming performance, making them an enticing option for those who want a slim laptop on the go, but a powerful gaming rig when you plug into the eGPU at home.

However, the latest 2023 installment of the ROG XG Mobile won't come cheap, as it features Nvidia's flagship GeForce RTX 4090 (in its mobile form), one of the best graphics cards for gamers.

The ROG XG Mobile is an external graphics dock that Asus introduced back in 2021 for the company's premium ROG Flow X13 (GV301/GV302), ROG Flow Z13 (GZ301), and ROG Flow X16 (GV601) laptops. It connects to the host device via a proprietary PCIe connector, so the ROG XG Mobile isn't compatible with notebooks outside of the aforementioned ROG Flow units. However, the most significant benefit of the connector is that it provides a PCIe 3.0 x8 highway for communication between the ROG XG Mobile and the host. The theoretical bandwidth for a PCIe 3.0 x8 connection is 63 Gb/s, around 57% higher than Thunderbolt 4 (40 Gb/s).

Aesthetically, the ROG XG Mobile hasn't changed much since its conception. The dock still measures 21.7 x 16.5 x 3.26 cm, roughly the size of a hardcover book. It has a similar footprint to the 2022 model, but is slightly bigger than the original one. Nvidia's GPUs have become more thermally demanding, after all. Because of that, the ROG XG Mobile has gained some weight over the years as well. The 2023 and 2022 models weigh 300 grams and 200 grams more, respectively, than the 2021 model.

ROG XG Mobile (2023) Specifications

The most prominent upgrade for the ROG XG Mobile 2023 resides under the hood. This year's model taps into Nvidia's GeForce RTX 4090 Laptop GPU (150W). It's a significant improvement over the previous model powered by the Radeon RX 6850M XT (165W) in terms of performance and power efficiency. Cooling comes in the shape of a vapor chamber on the GPU die, assisted by a standard heatsink and a small cooling fan with red illumination visible from the front of the dock. The GeForce RTX 4090 Laptop GPU has a configurable TGP between 80W and 150W, so consumers get the highest configuration here. Logically, it can't compete with some overclocked GeForce RTX 4090 Laptop GPUs with a 175W envelope, but that's a story for another day.

The ROG XG Mobile obviously can't obtain all the power it requires from the laptop. Despite using mobile graphics cards around the 150W range, the dock has always included a big power adapter. The first ROG XG Mobile came with a 280W unit. Since then, Asus has upgraded it to 330W for even more power headroom for other devices.

The ROG XG Mobile also doubles as an I/O hub, but that feature will require a USB 3.2 Gen 2 (10 Gb/s) connection to the laptop as well. While the first dock only had a Gigabit Ethernet connection, models from 2022 and forward rock a 2.5 Gigabit Ethernet port. Asus also revamped the USB ports, making them faster. The ROG XG Mobile 2023 offers a combination of three USB 3.2 Gen 2 Type-A ports and a USB 3.2 Gen 2 Type-C port, as opposed to the four usual USB 3.2 Gen 1 Type-A that had been around for the last two generations. The display ports and SD card reader are the two items that haven't changed.

Asus sells the ROG XG Mobile 2023 for a whopping $1,999.99. That's expensive given you can get a desktop GeForce RTX 4090 or one of the best gaming PCs for that kind of money and still have spare change. However, the 2022 model ($999.99) was substantially cheaper because Asus had chosen AMD's Radeon RX 6850M XT for the job. For comparison, the 2021 model with the GeForce RTX 3080 Laptop GPU sold for $1,099.99.

In other words, Asus is charging $900 or 82% more for the new version of its proprietary external GPU. On the bright side, there should be ample availability for the ROG XG Mobile 2023 given the price. We're sure that at least a few owners of previous Flow laptops will take the opportunity to upgrade their graphics capabilities without having to ditch their existing PC.