I have exactly the same issue, i get the screen full of ascii then a hard lock and have to power my system off.
I have tried redhat 7.3, 8.0, 9.0, FreeBSD 4.7, 4.8 and 5.0
All go into a full hardware lock when starting X with the Nvidia drivers. The non-accelerated drivers (nv) work fine.
It seems to be something to do with the Epox 8RDA+ mainboard as already mentioned above its probly a Bios issue.
I had no problems with my old mainboard, a ASUS A7V133 (KT133 Chipset)
So the problem is definately mainboard related, despite having no problems in windoze
Hopefully there will be a bios update for the 8RDA+ to fix the problem in the near future, but im not holding my breath.
Hope this saves some of you some troubleshooting time.