Complex sentence: It is not known weather a SATA drive that supports FUA write commands will actually honor the command and write data to disk platters as instructed; thus, Windows 8 and Windows Server 2012 instead send commands to flush the disk write cache after certain write operations.
Split into simpler sentences: It is not known weather a SATA drive that supports FUA write commands will actually honor the command, and write to disk as commanded. As proven support for FUA on SATA is unreliable, Windows 8 and Windows Server 2012, instead sends commands to flush the disk write cache after some write operations.