Triple RAID Storage Subsystem
10 SATA Ports and Two Hardware RAID Processors
The board has an abundant concentration of SATA ports to the bottom corner of the board - far more than the six SATA 3Gbps ports that the ICH10R Southbridge supports. So how does it do it? The answer lies beneath those extra heatsinks covering a handful of crucial ASICs.
Remember, ICH10 Southbridge chips don't support PATA controllers and we'll all need one of those to at least run the optical drives that are still transitioning to the SATA interface. To facilitate this, Gigabyte is using a JMicron JMB363 PCI Express chip (uses a PCIe lane from the ICH10R) which provides dual SATA 3Gbps ports and a single PATA controller. Still, these don't account for the SATA port count. Here's where things get a little interesting. Just below the JMB363, you'll find a pair of Silicon Image SiI5723 SteelVine hardware RAID processors. Each of these SiI5723 RAID processors uses a single SATA 3Gbps interface (riding off the JMB363 controller) and has a built-in port multiplier which supplies two SATA 3Gbps ports. Thus, both the RAID processors together support the four extra SATA ports which the Intel P45 chipset doesn't supply.
This isn't the first board that we've encountered with hardware RAID processors as the MSI P6N Diamond and the ASUS P5W DH Deluxe featured the older Silicon Image SiI4723 model. The new SiI5723 uses much smaller footprint thanks to new process technology and introduces a few new interesting RAID modes. Although being only a 2-port RAID controller and thus primarily supporting RAID 0 and RAID 1 modes, it introduces two new multi-RAID modes known as SAFE33 and SAFE50. Here's a quote from Silicon Image on what they do:-
" Multi-RAID modes automatically create two virtual volumes, one SAFE and the other BIG (also known as concatenation), and are designed to balance the benefits of capacity and protection with only two drives. SAFE50 divides the physical space on each drive equally to create each virtual volume. In SAFE33, two-thirds of the available physical space is used to create the BIG partition, and the remaining one-third is used for the SAFE partition."
So Safe33 and Safe50 are alternative RAID modes to get the most out of your RAID subsystem. Of course if you require RAID 5 across your four hard drives, you can depend on the motherboard's native SATA RAID controller from Intel. In addition to hardware RAID processors freeing up your CPU processing overheard, the bigger highlight is that they don't require any configuration or drivers and work independently of the operating system used.
In all, the Gigabyte GA-EP45-DQ6 supports a total of three independent RAID subsystems - one software-based from Intel, and two hardware based from Silicon Image.