Promise FastTrak TX2300 SATA controller - slow performance

As part of setting up a back-up system, I'm testing the copying of a 36 GB BKF file.

When copying between two SATA drives, both connected to the Promise FastTrak TX2300 SATA controller, the copy takes approx. 1.5 hours. If either of the drives is connected to the on-board SATA controller, with the other on the Promise controller, the copy takes 10 minutes.

I've tested this on two different PCs, tested both of the ports on the Promise controller, and the results are the same.

Can anyone offer advice on how to improve the performance when using just the Promise controller? My preferred PC for this role doesn't have an on-board SATA controller, so I'd rather just use the Promise one.

Thanks.

Thanks for the reply (and apologies for my late one).

Ok, I accept that it's a budget card, but I think it's reasonable to expect a two-port card to be able to host two drives and perform better than this. I don't need a RAID set-up, just simple SATA connectivity for a PC that didn't have a SATA controller. If this performance is expected, then how do Promise justify selling it?

Ideally, I would have a 'master' data drive connected to the SATA controller, and other removable data drives also. If I have only one usable SATA connection, I'm reduced to using USB 2, which is much slower (30 minutes to copy said BKF file).