Heres the thing quickly - It may help someone
I got a new P4 256meg ram
total hard drive space = 200 gig from 3 physical drives
also 1 DVD burner which filled the allocation of the IDE ports.
Put the last drive in and had problems with speed of the drive.
bechtesting revealed that it compared slower than a really cheap drive at a scale of 4 ... mines showed 3!!!!
usual probs like dropped frames etc..
The ... Checked the Bios
Found that the IDE cable running to the drive was 40 conductor
The one running to the other 2 drives was an 80 conductor
took the 2 cables and compared them .. YEP seemed as if the ribbons were different so I changed them
TARAH !!!! perfect - drive now benchmarks ( instead of 3 ) 62 !!!
Moral ; Dunno - just had to ell someone !!!