I found the answer to the problem. I'm working on getting this fix implemented. It seems that there is a problem with the IDE driver for RedHat. It forces the OS to see a 40-pin connector regardless. Therefore, the hard drive gets stuck in ATA33 mode.
Here's the solution.
The solution I used was found in: 15. Red Hat Linux 7.2/7. 1 Enabling IDE Driver Beyond ATA/33