The third generation of NUCs will get a CPU upgrade as well. There will be two versions: one with a Core i3-4010U CPU, and another with a more powerful Core i5-4250U. Both of the units have new Haswell chips and will thus be able to run a lot more efficiently. The Core i3-4010U CPU will carry an HD Graphics 4400 part; the Core i5-4250U will carry a more powerful HD Graphics 5000 part.
http://www.tomshardware.com/news/Intel-NUC-Haswell-SATA,22989.html