|I'm not familiar with the 9300GE. If it's integrated, go into your BIOS setup and disable it. Then, install the 9800GT. Remember to connect your monitor to the new card. |
If the 9300GE is an actual card wedged into a PCIe slot, it should be pretty obvious that you'll have to remove it before you can install the 9800GT. Unless your board has two PCIe x16 slots and you'd like to use the 9300GE to drive a third display, which is also possible.
"will i notice any difference in gaming performance?"
Socket 939 | Dual-core Opteron 185 @ 3.2GHz | 4GB | 1.0TB | Win7 x64
GeForce GTX 460 1GB | X-Fi Ti Pro | A8N32-SLI Deluxe | Antec P182