i think we are talking about:
The new "Suspend to Both" feature will give Linux 3.6 hybrid standby capability. Mac OS X and Windows have offered such a feature for some time; it involves having the computer store its memory contents both in RAM and on the system disk during hibernation. A system that hibernates this way will usually wake up within a few seconds as if waking up from Suspend-to-RAM (ACPI S3); however, if power was disrupted during hibernation, for instance because a notebook ran out of battery, the system will restore the main memory contents from disk as it would after Suspend-to-Disk (Hibernate).