I’m going to mention hdparm in passing, mostly because I think it’s becoming more and more rare, with each passing hour, to find machines that need it, let alone people who use it.
Which is not the fault of hdparm. It’s an issue of hardware improvements over time … which suggests it still might be influential, if you’re working with older drives.
Drive lifetimes are limited though, and I have only one traditional IDE drive in the house now — in this machine — even if you can still find them online for fairly cheap.
Results, for what I remember, depend very much on the hardware and the tweaks you use, which implies that a certain measure of expertise is required if you’re going to see good results.
The converse of that is, it will take some time to learn what works and in the mean time, there is the possibility of screwing things up royally — as in, dead hard drive.
I leave it to you to decide if hdparm is worth tinkering with. Newer drives probably won’t see much improvement; old, old ones will go from junk to jewel with it.
And as a Parthian shot, I will only suggest this over a decrepit hard drive — with or without hdparm — any day of the week. :|