I have exactly the same problem, after installing the FX5200 driver (NVIDIA-Linux-x86-1.0-4496-pkg2.run), the X server cannot be started in SMP kernel mode , but everything works well in non SMP mode. I attached the XFree86.0.log file .
By the way, when booting on the RH9 CD (on a P4 2,6C HT + FX 5200), the installation process failled when trying to launch the graphical mode using the VESA generic driver. The screen goes black without any signal. I have to restart it and run the installation in text mode. With RH8 everything is OK.
If someone has some information ...
Thanks in advance.