Is how the 9800 works with the rest of the system?
I mean that, if you buy an expensive videocard, you should have the rest of your system ready to properly use it so that you will not stress yourself over other computer components that are, compared to what your (new) videocard can/has to offer , suddenly outdated.
The reason I've been getting Geforce cards is because they're easy for people that don't know what they're doing. I've heard that ATI cards can be a lot more work to get to run with games.
Install the videocards, install drivers and it works. If it doesn't, well, then you may have caused a problem. Most likely the result of 'not knowing what you're doing'
Refer to the manual(s) and articles concerning videocards when installing and configuring a videocard.
Nvidia and ATI cards both work that way. However, you can choose to install the software found on the CD-ROM and/or found with the drivers that may offer different options.