I have an old 500gb IDE Seagate HD and I've been thinking of swapping it out for an SATA drive (prob the samsung spinpoint HD). While I'm at it, I'll prob get an SATA dvd burner as well and keep the old seagate hd as storage. Question is, is there a noticeable difference between the two nowadays. Doing a quick google search, I'd get hits back from 2004 that say there's a negligible difference, but how true is that with today's hardware? Thanks.
There will be a difference, but most likely it won't be due to the interface (IDE vs SATA) rather it will be due to platter density. Actually, it's only been fairly recent that hard drives have passed the 100MB/s barrier that was the limit of ATA100. Of course, SATA also brings AHCI, NCQ, hot-swapping, and better cable management.
For example, your 500GB IDE drive may have 3 or 4 platters, depending on how old it is, and takes longer to find data. The samsung 500G F3 is a single platter drive that packs the data in tighter (and based on reviews can have a max sequential read of ~140MB/s). I would benchmark your current drive on HDTach and compare it's speed to newer SATA models. I predict that it's probably in the 60MB/s max neighborhood.