I have a new Thinkpad Yoga 14 Laptop with i7 5500u processor and 16GB RAM, running Windows10 64 (freshly upgraded from win 8.1 64, where I had the exact same problem). Both with the 1.9.5 and the 1.9.3 drivers, Cubase 8 64 would not let me select the CI2+, claiming the processor does not have enough power (pop up window before automatically reverting to the previous driver/device), which appears strange at best, with these specs. I had no such problems on my old laptop running a Core2Duo T7700, through all possible generations of Cubase and Windows over the last number of years.
Both processors are compared on
http://www.cpu-world.com/Compare/190/Intel_Core_2_Duo_Mobile_T7700_(BGA)_vs_Intel_Core_i7_Mobile_i7-5500U.html
and, as expected, the i7 is ahead in any respect, so it cannot come down to processing power. Neither is Windows 10 at fault, it also runs on the old laptop.
Thanks for any pointers.