ICH7 is faster !
The Silicon Image 4723 is a real hardware RAID controller. I takes one of the four ICH7 SATA ports and lets you connect 2 HDDs to it which can be run in hardware RAID0 or RAID1.

The Silicon Image 4723 is the reason you only get 3 ICH7 ports since the 4th port is hard-wired to Sil =)

I succesfully ran RAID1 and RAID0 on this controller with a recent -mm kernel. While the RAID worked just fine, it was very slow. I ran some tests and was dearly disapointed. If you want to run a RAID0 or RAID1 use Linux SoftwareRaid but stay away from EZ-BAckup!.

If you remove both EZ jumpers you can use the right EZ-Backup port as the 4th ICH7 port.