I have a large city which is currently grabbing memory far too quickly, i have about 16 512x512 bmps tiled on the buildings but the memory drain is too high, am i able to use Jpegs? Any advice on how to free up Ram?

well you best bet is to figure out to get smaller textures in there without losing much detail other than that, there is not much you can really do, you cant use jpegs unless someone were maybe able to write a dll to read them, and then you'd have to use a material that switches the skin1 out with that read bmap and apply that to the walls which would take up more cpu power and gpu power, and would be a ton of trouble.

1) .dds will be better I think (small file size)