|Do you understand what "Idle" means? 97-99% idle means only 1-3% of the CPU is being used. So let me put it this way - are you concerned that 1-3% of the CPU is being used when the system is sitting idle (aka not running any programs)?|
As has been explained about IDE channels, there are 2 (primary & 2ndary) & each channel can support 2 devices (master & slave). So the device possibilities are:
primary master + primary slave
2ndary master + 2ndary slave
And there are optimal ways of configuring the devices depending on how many devices you have & whether they are HDDs or optical drives. I won't bother listing the possibilities because you have provided no systems specs.
As for the listings in Device Manager, it's not unusual to have duplicates. If you're concerned, right click on each one & click uninstall (if it will let you). Uninstall all you can, then reboot & Windows will re-install what it needs.