My first though is that Windows has decided it likes PIO mode.
Windows monitors the errors that occur on an IDE channel, when a certain number have happened (and there will always be SOME errors) it drops the IDE channel and all drives on it to PIO mode - pre-UDMA, maxes out at 16MiB/s, and eats CPU cycles.
The only way to change this is to delete the IDE channels from device manager and reboot, whereupon Windows will redetect them and install them as new devices with no errors ever.
The issue is that Windows will log the LIFETIME errors on a channel.... a silly idea imho.
But I have nothing to go on here and that is pure speculation. Full system specs please, along with further error details!
Do you mean it lags no matter what program accesses the drive for what reasion? Even say, playing a Music CD or a Video DVD, or just when ripping burning with whatever app you use?
I had this same problem. I had to load the drivers for the ide controler. The drive still locks up my computer for just a sec when it is first accessing but at least it does not make my mouse lag any more. What is your motherboard? Mine came with the drivers on the cd but I never thought to load them. My mobo is a MSI 965 Platinum.
How can it be a resources problem? This system doesnt twitch when Im watching a dvd and playing a videogame at the same time. And its not one specific application, its just any time the drives are in use.