my dual channel DDR 400 RAM won't work on any linux distro

Do you perhaps have a video card with 128MB on board? I had the same symptoms as you, and it turned out to be the vesafb driver. It basically tries to ioremap the entire framebuffer and can't fit it in the reserved area because it's only 128MB. You can either boot with vga=0 or some such text mode, which disables the vesafb, or patch vesafb to only ioremap the space needed for the video mode selected. BTW, the same applies to rivafb and others I suspect, if your video card has 128MB ram.

-Walt