If I have a SCSI hard drive(and run Windows XP), would it make any notable difference to the pc preformance/ speed? or would it only be obvious when many graphic softwares are run at the same time?
Well it depends on the drive as well as the SCSI controller. The fancy new SCSI controllers packing 64MB cache running a 320MB link with insanely long device chains ... coupled with a nice Seagate SCSI320 drive ... that's a noticeable performance jump ... of course it'll cost a small fortune.
But seriously, IDE drives have improved a lot over the last decade and given the price difference, prolly a better choice if you've not purchased the other stuff yet. If you aleady have the SCSI stuff, I'll tentatively say yes it'll be a noticeable improvement but i need to know what im comparing