Introduction

Thunderbolt 3 (TB3) is fast becoming the connection of choice in most PCs due to its ability to leverage the new USB 3.1 Type C-connector to provide 40 Gbps bandwidth over a PCIe bus to the CPU. The port has the capability to drive two 4K displays simultaneously, deliver up to 100W power for device charging, provide a 10Gb Ethernet connection, and act as a hub for connecting a host of USB and DisplayPort devices all at once — but its most attractive feature to many has always been the ability to connect an external GPU.

There was a minor kerfuffle when consumers learned that not all TB3 implementations were created equal, resulting in lots of unhappy XPS 13 and XPS 15 users. Intel gives OEMs the flexibility in allowing 2- or 4-lane PCIe connectivity via TB3. When used to connect an eGPU, a 2-lane connection results in roughly only 16Gbps of bandwidth rather than the 40Gbps that is advertised. It has been traditionally the opinion that 2-lane PCIe connectivity bottlenecks eGPUs due to the decreased bandwidth, but going by a comparative benchmark run by YouTuber Stephen Burgess of OwnorDisown, it seems that notebooks can not only do okay with an eGPU running over a 2-lane implementation, but it is even possible for them to outperform a 4-lane notebook with a faster CPU in a few cases. Let's have a look at OwnorDisown's benchmarks:

