You will not need a controller card unless you plan on connecting more than 4 devices inside your computer on the two controllers, ie 2 hard drives, 2 CD/DVD RWs, etc. Most motherboards come with a primary and secondary controller. The primary IDE controller can only have two devices, same with the secondary IDE controller. To add, say, another hard drive, you would need an IDE or SATA contoller card to plug into a PCI slot to expand your system.
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