The latest 6th generation Intel® processors with U/Y platforms support up to power state C10. The technical data specification is below:
http://www.intel.com/content/www/us/en/processors/core/6th-gen-core-family-mobile-u-y-processor-line... Datasheet, Vol. 1: 6th Gen Intel® Processor for U/Y-Platforms
As reference, I recommend to review the following document.
https://software.intel.com/en-us/articles/power-management-states-p-states-c-states-and-package-c-st... _Toc383778910 Power Management States: P-States, C-States, and Package C-States | Intel® Developer Zone
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