Try this to fix the AGP8X problem:
1. Uninstall the Catalyst Control Panel. Don't reboot.
2. Uninstall the Catalyst Drivers.
3. Reboot into safe mode.
4. Use
Driver Cleaner and clean all ATI stuff from your system.
5. Reboot into windows.
6. Cancel out any attempts by Windows to install drivers automatically.
7. Run the install program again. Don't reboot.
8. Go into Services and put ATI Hotkey Poller and ATI SMART services into manual mode.
9. Reboot.
10. After windows has completely loaded, go back into services and place ATI SMART service into Automatic and start it.
11. After the ATI SMART service has done it's thing, reboot.
12. Check the SMARTGART tab in the Display Control Panel. You should have AGP8X and Fast Writes on now.
Try this to fix the flickering:
1. Check the Displays tab in the Display Control Panel. Click on the Monitor tab.
2. On the Attributes tab, uncheck the Use DDC Information checkbox.
3. Then manually set the highest resolution and refresh rate that you want your monitor to be run at.
4. Click on the Advanced tab. Enable Horizontal, Vertical, and Composite synchronizaton. Apply settings.
5. Your flickering may now have gone away. You might have to adjust your monitor's horizontal and vertical sizes and positions now.
Both of these procedures have worked for me with my Radeon 9600 Pro. I hope they work for you as well. Good luck.