Alienware don’t just use Nvidia graphics card only for their high-end pre-built systems, but they also use Radeon RX 6800 XT Graphics Card too as shown in the photos below.
Taken from Videocardz … A Reddit Hardcorex has uploaded photos of the Radeon RX 6800 XT graphics card that is being used by Dell Alienware systems. Those pre-built gaming PCs also come with high-end graphics cards which are not always visible through closed chassis. One of such system is the new Alienware from Dell.
Dell Radeon RX 6800 XT is a triple-fan and dual-slot. The cooler design does remind us of the Radeon VII featuring Vega 20, but we have already seen a much better-looking implementation of VII’s design by LENOVO for their Legion prebuilt systems. It is a very plain design with PCB without any marking or logos. In fact, the color of the PCB may surprise some of our readers, because not very often we get to see green PCB, even in ultra-cheap models.
Source: Videocardz, Reddit