Intel's Guide To Achieving S0ix Low-Power States On Linux
Intel's 01.org open-source portal has published a guide to utilizing Intel S0ix power states on Linux with supported SoCs and how to debug power issues around this low-power idle state where parts of the SoC are turned off when not in use.
It's possible to find out if your Intel system supports the low-power S0 Idle by looking at an ACPI dump of the system, enabling suspend-to-idle S0ix via a sysfs interface, and other possible tweaks. When using the newer Linux 4.17+ kernels there are also various power savings improvements around Display-OFF, SATA, and Thunderbolt.
See this 01.org guide if you want to learn more about S0ix power-savings on Linux.