Ultra66 Controller Card Problem

Installed a WDC 8.4 gig, 5400 rpm, ATA/66 hard drive and Promise Technology Ultra66 controller card, in 5-yr old Micron PC Pentium Pro 200 Mhz, 128 mb ram, Win98SE. Hard drive and controller card “work fine” at 33 mb/s setting but cause OS to “hang”at 66 mb/s setting. Have run WDC diagnostics software and hard drive checks out fine. Vendor provided replacement controller card and 80-wire/40-pin IDE cable. Have updated the bios AMIbios (1.00.18CS1). PC has Intel Venus motherboard Natama 440FXchipset. Are there bios settings that I need to check/change? Or, is this simply an incompatibility problem between controller card and motherboard/bios?