Lenovo demonstrates NVMe M.2 alternative to Thunderbolt for high-end external desktop GPUs on AMD-based notebooks
Even though Thunderbolt is already an open standard, it still remains an Intel-exclusive feature until AMD is supposed to launch the first desktop and mobile platforms to support it in 2022. At CES this year, Asus presented an interesting Thunderbolt alternative with the upcoming ROG Flow X13 laptops that use a special port to connect to external discrete cards, but it looks like Lenovo has come up with a simpler solution that does not require proprietary designs.
Lenovo’s Chinese sub-brand Koshin demonstrated the solution that employs a modified M.2 2280 slot on an Air 14 laptop equipped with an AMD Ryzen 5 4600U APU plus an external Nvidia RTX 3090 card. This is obviously not as fast as a desktop PCIe X16 connection since it uses a 4-lane PCIe 3.0 interface, yet it still delivers good results. The modification only requires an M.2 to PCIe adapter cable, and of course, the chassis needs to be modded with a small opening in the bottom cover to allow for the cable extension. As far as performance goes, the external RTX 3090 card connected to the Air 14 notebook was able to score 14,008 points in the default 3DMark TimeSpy test, which is comparable to the 15,000 point score recorded by a desktop RTX 3080 coupled with an Intel i9-9900K CPU.
This example is probably not really that cost effective, since the high-end GPUs are quite shorted right now. Apparently, the M.2 solution for external GPUs is quite common among diehard modders, but Lenovo now has the opportunity to mass-produce such an implementation. It would eventually allow gamers to buy very affordable and energy efficient AMD laptops without a mobile dGPU, which then can be connected to a powerful external GPU and still perform close to desktop standards at a considerably lower price.