The small form-factor X1 PCs from Shuttle are able to handle 4K games thanks to the inclusion of Nvidia's GTX 1060 GPUs. The reduced size comes at a premium, though, with the i7 variant priced at US$1709 and the i5 variants costing around US$1500.
https://www.notebookcheck.net/Shuttle-launches-the-X1-Mini-PC-with-GeForce-GTX-1060.241636.0.html