With the U4 UD, Gigabyte offers a very lightweight subnotebook with a very rare but powerful CPU. However, it didn't perform as well as we had hoped in our review. But the Gigabyte U4 ultimately won us over, despite there being a few points of criticism.
https://www.notebookcheck.net/The-Gigabyte-U4-UD-subnotebook-wastes-potential-in-the-test-despite-its-i7-CPU.581851.0.html