Re: Video Ram not detected
NVIDIA doesn't provide VBIOS updates, as that is the responsibility of the videocard vendors. Not all of them provide updates, however some do.
Updating any BIOS carries some risk, as you are rewriting code on the chip. Some vendor's highlight the risk more than others.
You can use the NvAGP option with a value of 1 to force the nvidia driver's AGP support.