More SATA, More RAID, More Ports
Four SATA channels, ATAPI support, Matrix RAID, easy RAID migration, hot plugging and command queuing are standing by.
Another leap has been made with the Serial ATA controller. While the component that is part of ICH5 and ICH5R is a rather simple one, Intel has now upgraded it to become a real AHCI device (Advanced Host Controller Interface). As a result, Windows logs it in as an SCSI or RAID controller device. As I mentioned earlier in this article, this is also the reason why you will have to reinstall your operating system when upgrading from an 800 to a 900 chipset if you are running Windows on an ICH5 RAID drive. Unfortunately, software compatibility has gone.
The 900 chipset family finally offers four SATA ports. All of them are capable of running at 150 MB/s max. In addition, ATAPI support has been introduced as well so as to be ready for optical drives that will be increasingly equipped with an SATA interface rather than UltraATA.
There are several changes to the RAID capabilities, too. As before, a simple RAID 0 stripe set can be instituted in order to speed up your drive subsystem. As an alternative, you may of course chose a RAID 1 setup that mirrors all the information on a second drive in real time. Thanks to the four SATA ports, you can do both - provided you've got two hard drive pairs.
Whenever you install a fresh copy of Windows, you need to consider whether you want to start with a RAID-ready setup or a simple drive. Basically, creating a one-drive RAID is what I consider to be a RAID-ready setup. This config is required to easily upgrade to RAID 0 or 1 after adding a second hard drive (which is done in Windows). Intel calls it 'RAID migration capability'.
The downside is that the RAID-ready system drive will not be able to run on computers that do not have the ICH6R SATA controller with Intel Application Accelerator 4.0 RAID drivers installed - if that is important for you to know.
Also, Intel now allows for a spare drive to be added. This one is useful for RAID 1 setups and will automatically be used to rebuild the array if one of the member drives should fail. We found it interesting to see that Intel didn't provide options to run RAID arrays with three or four drives either. As the chipsets we're dealing with are desktop products, the focus was elsewhere: Matrix RAID.