Everytime I've bought a brand new hard drive, regardless if USB, NAS, or just another one to put into the box, the music files or video files I put onto it sound fresher, crisper, more open and just better overall.
So thereÂs something to be said for newe HDDs.
I've also heard slight diffs from the format of the disc. Finding FAT to 32 sound more open than NTFS. Go figure. Maybe it was the drive materials... the format... the cabling... beats me. But new drives with freshly transfered files always sounds best to me.
There is too a thing called "bit decay" or something like that which says files stored on magnetic mediums tend after time passes, to begin deteriorating. Slowly. So slowly in fact it takes a while. A good while and a side by side comparison to truly notice these desparities.
I've discovered this in my own drives and pcs but only after some years of storage. 2-3 perhaps. Wiping/reformating and reloading the files usually fixes that incidence. again, it's near non noticeable unless you compare similar files on an older drive and a new one.
ThatÂs why backing up and reloading from time to time is important . For the more anal of us, and to be sure it is more pertinent to redoing the OS about once every year to two years depending upon usage, in addition to the norm of error checking and defragging. Your disc (s) .
In general if the OS is on the drive with the media files, and you are at or above 75% capacity, things will begin to act up and/or slow down. If at all possible, and today it is more than ever before, add another storage center. usb, NAS ESATA, etc., or at least another physical Drive into the box.
unless you have on hand some partitioning software and can create or split, your drive into two, with one being a logical drive merely for storage data.... get a secondary drive!. Things will spped up and become more stable too.
SS drives now, in the USA anyhow are still very costly and not terribly large. There are also bugs with interfacing them into 64 bit OS, and OS older than Win 7.... or so my Geek buddy is finding out with his new 30GB SS unit where he places only his Wind 7 64 gbit OS.
Even adding a new ROM drive for ripping will aid the freshening up sound of the ripped files to some degree.
your results may vary, but these thoughts are those which I've discovered over the past eighht to ten years, using various OS, boxes, AND drives in various configs.
Good luck.