Ahh, you never can have too much space, can you?
Originally, I was going to say it's the Promise 133TX2. I'm using the one that came with my Maxtor 160GB 8MB Cache. I actually have two of these identical drives connected to the controller card, both as master on separate IDE chains, and I'm not impressed with the copying speed between the two drives. I'm certain it is the controller at fault as the drives do not have this lag when connected to the mainboard IDE chains. I'm using the mainboard chains for optical drives though, as the Promise 133TX2 is not meant for CD-ROM or CD-RW drives. Another problem I noticed is that I have to disable "Pass Windows flush-drive-cache commands to disk drive" under the Device Manager, otherwise things like MP3's skip. With this turned off, the drive's performance decreases, but I'd rather that than have skips in my MP3's. It's simply intolerable!
I do have a Promise 100TX2 that I hear is better than the 133TX2. Why haven't I installed the 100TX2? Laziness.
I hope when I install that, both disk drives can return to peak performance and still have the flush-drive-cache option enabled.
For your predicament, wicked1, if you have narrowed down that it isn't the controller card, did you narrow down other hardware like the IDE cables? I assume you are using 80-wire ATA 100/133 cables and not 40-wire ATA 33 ones.
No, I like women.