The external graphic enclosures are designed to provide graphics acceleration to the portable computers, but the common problem with the currently available eGPUs is the size. They sure can improve the graphics performance of your ultrabook, but they all suffer portability problem.
“Sonnet’s eGFX Breakaway™ Puck is an extremely-portable, high-performance, all-in-one external GPU for Thunderbolt 3 computers that provides accelerated graphics and multi-display connectivity. With a Puck connected to your computer, you can dramatically accelerate popular graphics-intensive games and pro applications anywhere.”
You can choose between two models, One with a Radeon RX 560 GPU (GPU-RX560-TB3) is priced at $449, and the other with a Radeon RX 570 GPU (GPU-RX570-TB3) will cost you $599. You can get the optional VESA mounting bracket for $59.