*Chipset
VIA® VT8363 (KT133) AGPset supports 200MHz FSB and 3.3V PC133 SDRAM & VC133 VCM (Virtual Channel Memory)
VIA® 82C686A South Bridge & Super I/O to Support ACPI and SMBus.
Onboard Promise® PCI-ATA100 Controller
*IDE Ports
2 x Ultra DMA/66 EIDE Ports
Support CD-ROM, DVD-ROM, CD-R/RW, ZIP and LS-120 Drives
Did you install the Promise Ultra 100TM IDE Controller Driver?
And do you you have the UDMA/100 ribbon cable connected to the Promise controller and not the normal DMA/66?
Again If it's the plain A7V it doesn't support UATA/133 and it only supports UDMA/100 (same thing as UATA/100) if you use the onboard promise controller. But you probably have to install the Driver for it to function.
Here is the page with the Drivers:
http://download.asus.com.tw/mb_dl_menu.asp?l1=1&l2=10&l3=1&mid=1
But they are only listing Drivers for Win9x/ME/NT4/2000.