HighPoint onboard ATA-100 RAID controller: Separate Circuit?

[pmistry 0]

I would say it is separate reason being is that I used to own an

Abit KA7-100 motherboard, that was based on the VIA KX133. The VIA KX133 only supported UDMA/66 but the Highpoint 370 controller supports UDMA/100. Therefore you would need 2 different circuits right?

 

Also, when you install the OS, the OS detects it as a SCSI/RAID device thus leaving me with the conclusion that it is like an onboard LAN or onboard sound, it is a separate PCI device, just not in a PCI slot.