scsi problems

I have a scsi controller atp29160 all the drives and system act strange…. yesterday i left the room and retuned my system was locked i keep trying to reboot then i found the drive was not powering up the thought it was dead, so i hooked up my other drive its a 160 drive now when booting this drive the scsi card would drop the transfer rate to 40 i checked and its set for 160.
I shut the system down and left it for the night now i rehooked the drive that would not boot and the keep the other drive connected the drive that would not spin up is working and the other drive is showing a 160 transfer rate, could this be the controller card?….

Thanks gary