Sounds like you are using one of the Fedora or RedHat distros, and an older one at that.
Unless you must use that particular distro, I would suggest you check out Ubuntu Linux. Look at the LTS (Long Term Support) versions.
Ubuntu does a good job of taking advantage of the ATI Proprietary drivers that are available for applicable GPUs.
That being said, how are you using the system, with what apps, to need three 30" monitors? Also, what are the basic specs for the system you are using? Make sure you include the make/model of your motherboard and power supply.