Anaconda for FC4 x86_64: GeForce 6150 bug?

[dondi_2006]

Hi,

this is a new info and request for help on the
problem I'm having with installing FC4 x86_64 on a
ASUS A8N-VM CSM motherboard with:

nForce 430 / GeForce 6150 chipset
one maxtor SATA drive
x2 Athlon

Yesterday I posted the "install on SATA drive on ASUS A8n-VM CSM, nforce 430" message, saying that onboard VGA was not working: the screen was messed up (*even* in text
mode, lowres, fixed resolution, nofb....).
Even with BIOS upgraded to latest version.

Later on I:

1) started the installation of FC4 x86, with the same
   good discs I had successfully used for my previous PC
2) had NO problems at all with graphics: both the initial
   screen in text mode and the graphical anaconda gui
3) ran the mediacheck utility of my FC4 x86 disc 1 on the
   Fc4 x86_64 disc which screws up as above, and it passed
   the test
4) loading the nv_sata driver, managed to install and
   boot FC4 x86 on this box.

To me this means that there is some bug, limit or VGa
setting requirement in Anaconda for FC4 x86_646 which is
absent in the FC4 x86 version. What could it be? Is it
known, and how can be fixed? If it's not Anaconda, where
is the problem?
Any hope it would be different with FC5t2 for x86_64?

Any help is greatly appreciated,

D.