Promise Ultra ATA 66 controller vs. FC1

I have a Promise Ultra 66 eide controller, but think it is only being acessed at 33 Mhz. I have looked around, but have not found how to ascertain what rate Fedora is using it at.
Is there a way to configure FC1 to use it at 66MHz?

cat /proc/pci|more:
 Bus  0, device  15, function  0:
   Unknown mass storage controller: Promise Technology, Inc. 20262 (rev 1).
     IRQ 7.
     Master Capable.  Latency=64.
     I/O at 0x1090 [0x1097].
     I/O at 0x1084 [0x1087].
     I/O at 0x1088 [0x108f].
     I/O at 0x1080 [0x1083].
     I/O at 0x1040 [0x107f].
     Non-prefetchable 32 bit memory at 0xf4040000 [0xf405ffff].

dmesg|more :
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx