As announced by Nvidia, Portal RTX will include high-resolution textures, high polygon models, full ray tracing support, as well as DLSS 3.0, so it will obviously work the best on Nvidia's graphics cards, although it should work with any GPU with support for DXR and Vulkan ray tracing.
With DLSS Super Resolution and DLSS Frame Insertion, Nvidia claims the game will get up to 2.8x higher performance.
On the other hand, all of those graphics improvements come with a high price, and the announced hardware requirements are quite high.
According to the announced requirements, you will need at least an RTX 3060 to get 30FPS at 1080p resolution, with DLSS that is. In order to run the game at 60FPS at 4K resolution, you'll need an RTX 4080 with DLSS enabled.