Fake RAID, or hardware-assisted software RAID is a low end technology developed as a means to market RAID to consumers at a reduced cost, while trying to claim the system is true hardware RAID.
A hardware-based array manages the RAID subsystem independently from the host. It presents a single disk per RAID array to the host. Real RAID controller cards handle all the actual drive communications. The user plugs the drives into the RAID controller and then adds them to the RAID controllers configuration, and the operating system won't know the difference. Some computer motherboards are claimed to have onboard RAID. This is typically NOT REAL HARDWARE RAID. It is "Fake RAID."
FakeRAID, also known as ‘HostRAID’ has many of the faults of both Hardware and Software RAIDs without any real benefit. FakeRAID is a combination of a specialty system driver and a modified drive controller chip. On almost all consumer grade motherboards on-board RAID will be "Fake" raid. It is possible however to get a motherboard with a dedicated hardware RAID controller. In fake RAID during bootup the RAID is implemented by the firmware and, once the operating system has been more completely loaded, the drivers take over control. Consequently, such controllers do not work when driver support is not available for the host operating system.
The only perceivable real advantage to using Fake RAID over a software RAID is that the boot drive itself when configured with a redundancy mode is also somewhat protected, but not entirely. In software RAID of the boot drive, a single drive, fails, the system cannot boot unless an alternative boot media is presented to the system, such as a bootable USB Flash Drive.