make the MB accept high density ram modules

[chriz74]

Sorry for the double post but maybe this is the right place to ask.

Hello, I have this MoBo -> K8NF6G-VSTA.
It has an Nvidia nForce 405 chipset, I also have two high density ddr 400 modules (1GB each). I read around that this kind of ram should be compatible with nForce 4 chipset however the MoBo only reads 512Mb out of any of those modules and it also fails to post if only one module is inserted. Is there a way to modify the BIOS so that the ram works? Maybe updating the NVMM Nvidia Memory Manager Module? I opened the bios with mmtool but I can't see any NVMM inside.